/* libs/opengles/primitives.cpp
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "context.h"
#include "primitives.h"
#include "light.h"
#include "matrix.h"
#include "vertex.h"
#include "fp.h"
#include "TextureObjectManager.h"
extern "C" void iterators0032(const void* that,
int32_t* it, int32_t c0, int32_t c1, int32_t c2);
namespace android {
// ----------------------------------------------------------------------------
static void primitive_point(ogles_context_t* c, vertex_t* v);
static void primitive_line(ogles_context_t* c, vertex_t* v0, vertex_t* v1);
static void primitive_clip_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static void primitive_nop_point(ogles_context_t* c, vertex_t* v);
static void primitive_nop_line(ogles_context_t* c, vertex_t* v0, vertex_t* v1);
static void primitive_nop_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static inline bool cull_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static void lerp_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static void lerp_texcoords(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static void lerp_texcoords_w(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static void triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static void clip_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2);
static unsigned int clip_line(ogles_context_t* c,
vertex_t* s, vertex_t* p);
// ----------------------------------------------------------------------------
#if 0
#pragma mark -
#endif
static void lightTriangleDarkSmooth(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
if (!(v0->flags & vertex_t::LIT)) {
v0->flags |= vertex_t::LIT;
const GLvoid* cp = c->arrays.color.element(
v0->index & vertex_cache_t::INDEX_MASK);
c->arrays.color.fetch(c, v0->color.v, cp);
}
if (!(v1->flags & vertex_t::LIT)) {
v1->flags |= vertex_t::LIT;
const GLvoid* cp = c->arrays.color.element(
v1->index & vertex_cache_t::INDEX_MASK);
c->arrays.color.fetch(c, v1->color.v, cp);
}
if(!(v2->flags & vertex_t::LIT)) {
v2->flags |= vertex_t::LIT;
const GLvoid* cp = c->arrays.color.element(
v2->index & vertex_cache_t::INDEX_MASK);
c->arrays.color.fetch(c, v2->color.v, cp);
}
}
static void lightTriangleDarkFlat(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
if (!(v2->flags & vertex_t::LIT)) {
v2->flags |= vertex_t::LIT;
const GLvoid* cp = c->arrays.color.element(
v2->index & vertex_cache_t::INDEX_MASK);
c->arrays.color.fetch(c, v2->color.v, cp);
}
// configure the rasterizer here, before we clip
c->rasterizer.procs.color4xv(c, v2->color.v);
}
static void lightTriangleSmooth(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
if (!(v0->flags & vertex_t::LIT))
c->lighting.lightVertex(c, v0);
if (!(v1->flags & vertex_t::LIT))
c->lighting.lightVertex(c, v1);
if(!(v2->flags & vertex_t::LIT))
c->lighting.lightVertex(c, v2);
}
static void lightTriangleFlat(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
if (!(v2->flags & vertex_t::LIT))
c->lighting.lightVertex(c, v2);
// configure the rasterizer here, before we clip
c->rasterizer.procs.color4xv(c, v2->color.v);
}
// The fog versions...
static inline
void lightVertexDarkSmoothFog(ogles_context_t* c, vertex_t* v)
{
if (!(v->flags & vertex_t::LIT)) {
v->flags |= vertex_t::LIT;
v->fog = c->fog.fog(c, v->eye.z);
const GLvoid* cp = c->arrays.color.element(
v->index & vertex_cache_t::INDEX_MASK);
c->arrays.color.fetch(c, v->color.v, cp);
}
}
static inline
void lightVertexDarkFlatFog(ogles_context_t* c, vertex_t* v)
{
if (!(v->flags & vertex_t::LIT)) {
v->flags |= vertex_t::LIT;
v->fog = c->fog.fog(c, v->eye.z);
}
}
static inline
void lightVertexSmoothFog(ogles_context_t* c, vertex_t* v)
{
if (!(v->flags & vertex_t::LIT)) {
v->fog = c->fog.fog(c, v->eye.z);
c->lighting.lightVertex(c, v);
}
}
static void lightTriangleDarkSmoothFog(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
lightVertexDarkSmoothFog(c, v0);
lightVertexDarkSmoothFog(c, v1);
lightVertexDarkSmoothFog(c, v2);
}
static void lightTriangleDarkFlatFog(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
lightVertexDarkFlatFog(c, v0);
lightVertexDarkFlatFog(c, v1);
lightVertexDarkSmoothFog(c, v2);
// configure the rasterizer here, before we clip
c->rasterizer.procs.color4xv(c, v2->color.v);
}
static void lightTriangleSmoothFog(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
lightVertexSmoothFog(c, v0);
lightVertexSmoothFog(c, v1);
lightVertexSmoothFog(c, v2);
}
static void lightTriangleFlatFog(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
lightVertexDarkFlatFog(c, v0);
lightVertexDarkFlatFog(c, v1);
lightVertexSmoothFog(c, v2);
// configure the rasterizer here, before we clip
c->rasterizer.procs.color4xv(c, v2->color.v);
}
typedef void (*light_primitive_t)(ogles_context_t*,
vertex_t*, vertex_t*, vertex_t*);
// fog 0x4, light 0x2, smooth 0x1
static const light_primitive_t lightPrimitive[8] = {
lightTriangleDarkFlat, // no fog | dark | flat
lightTriangleDarkSmooth, // no fog | dark | smooth
lightTriangleFlat, // no fog | light | flat
lightTriangleSmooth, // no fog | light | smooth
lightTriangleDarkFlatFog, // fog | dark | flat
lightTriangleDarkSmoothFog, // fog | dark | smooth
lightTriangleFlatFog, // fog | light | flat
lightTriangleSmoothFog // fog | light | smooth
};
void ogles_validate_primitives(ogles_context_t* c)
{
const uint32_t enables = c->rasterizer.state.enables;
// set up the lighting/shading/smoothing/fogging function
int index = enables & GGL_ENABLE_SMOOTH ? 0x1 : 0;
index |= c->lighting.enable ? 0x2 : 0;
index |= enables & GGL_ENABLE_FOG ? 0x4 : 0;
c->lighting.lightTriangle = lightPrimitive[index];
// set up the primitive renderers
if (ggl_likely(c->arrays.vertex.enable)) {
c->prims.renderPoint = primitive_point;
c->prims.renderLine = primitive_line;
c->prims.renderTriangle = primitive_clip_triangle;
} else {
c->prims.renderPoint = primitive_nop_point;
c->prims.renderLine = primitive_nop_line;
c->prims.renderTriangle = primitive_nop_triangle;
}
}
// ----------------------------------------------------------------------------
void compute_iterators_t::initTriangle(
vertex_t const* v0, vertex_t const* v1, vertex_t const* v2)
{
m_dx01 = v1->window.x - v0->window.x;
m_dy10 = v0->window.y - v1->window.y;
m_dx20 = v0->window.x - v2->window.x;
m_dy02 = v2->window.y - v0->window.y;
m_area = m_dx01*m_dy02 + (-m_dy10)*m_dx20;
}
void compute_iterators_t::initLine(
vertex_t const* v0, vertex_t const* v1)
{
m_dx01 = m_dy02 = v1->window.x - v0->window.x;
m_dy10 = m_dx20 = v0->window.y - v1->window.y;
m_area = m_dx01*m_dy02 + (-m_dy10)*m_dx20;
}
void compute_iterators_t::initLerp(vertex_t const* v0, uint32_t enables)
{
m_x0 = v0->window.x;
m_y0 = v0->window.y;
const GGLcoord area = (m_area + TRI_HALF) >> TRI_FRACTION_BITS;
const GGLcoord minArea = 2; // cannot be inverted
// triangles with an area smaller than 1.0 are not smooth-shaded
int q=0, s=0, d=0;
if (abs(area) >= minArea) {
// Here we do some voodoo magic, to compute a suitable scale
// factor for deltas/area:
// First compute the 1/area with full 32-bits precision,
// gglRecipQNormalized returns a number [-0.5, 0.5[ and an exponent.
d = gglRecipQNormalized(area, &q);
// Then compute the minimum left-shift to not overflow the muls
// below.
s = 32 - gglClz(abs(m_dy02)|abs(m_dy10)|abs(m_dx01)|abs(m_dx20));
// We'll keep 16-bits of precision for deltas/area. So we need
// to shift everything left an extra 15 bits.
s += 15;
// make sure all final shifts are not > 32, because gglMulx
// can't handle it.
if (s < q) s = q;
if (s > 32) {
d >>= 32-s;
s = 32;
}
}
m_dx01 = gglMulx(m_dx01, d, s);
m_dy10 = gglMulx(m_dy10, d, s);
m_dx20 = gglMulx(m_dx20, d, s);
m_dy02 = gglMulx(m_dy02, d, s);
m_area_scale = 32 + q - s;
m_scale = 0;
if (enables & GGL_ENABLE_TMUS) {
const int A = gglClz(abs(m_dy02)|abs(m_dy10)|abs(m_dx01)|abs(m_dx20));
const int B = gglClz(abs(m_x0)|abs(m_y0));
m_scale = max(0, 32 - (A + 16)) +
max(0, 32 - (B + TRI_FRACTION_BITS)) + 1;
}
}
int compute_iterators_t::iteratorsScale(GGLfixed* it,
int32_t c0, int32_t c1, int32_t c2) const
{
int32_t dc01 = c1 - c0;
int32_t dc02 = c2 - c0;
const int A = gglClz(abs(c0));
const int B = gglClz(abs(dc01)|abs(dc02));
const int scale = min(A, B - m_scale) - 2;
if (scale >= 0) {
c0 <<= scale;
dc01 <<= scale;
dc02 <<= scale;
} else {
c0 >>= -scale;
dc01 >>= -scale;
dc02 >>= -scale;
}
const int s = m_area_scale;
int32_t dcdx = gglMulAddx(dc01, m_dy02, gglMulx(dc02, m_dy10, s), s);
int32_t dcdy = gglMulAddx(dc02, m_dx01, gglMulx(dc01, m_dx20, s), s);
int32_t c = c0 - (gglMulAddx(dcdx, m_x0,
gglMulx(dcdy, m_y0, TRI_FRACTION_BITS), TRI_FRACTION_BITS));
it[0] = c;
it[1] = dcdx;
it[2] = dcdy;
return scale;
}
void compute_iterators_t::iterators1616(GGLfixed* it,
GGLfixed c0, GGLfixed c1, GGLfixed c2) const
{
const GGLfixed dc01 = c1 - c0;
const GGLfixed dc02 = c2 - c0;
// 16.16 x 16.16 == 32.32 --> 16.16
const int s = m_area_scale;
int32_t dcdx = gglMulAddx(dc01, m_dy02, gglMulx(dc02, m_dy10, s), s);
int32_t dcdy = gglMulAddx(dc02, m_dx01, gglMulx(dc01, m_dx20, s), s);
int32_t c = c0 - (gglMulAddx(dcdx, m_x0,
gglMulx(dcdy, m_y0, TRI_FRACTION_BITS), TRI_FRACTION_BITS));
it[0] = c;
it[1] = dcdx;
it[2] = dcdy;
}
void compute_iterators_t::iterators0032(int64_t* it,
int32_t c0, int32_t c1, int32_t c2) const
{
const int s = m_area_scale - 16;
int32_t dc01 = (c1 - c0)>>s;
int32_t dc02 = (c2 - c0)>>s;
// 16.16 x 16.16 == 32.32
int64_t dcdx = gglMulii(dc01, m_dy02) + gglMulii(dc02, m_dy10);
int64_t dcdy = gglMulii(dc02, m_dx01) + gglMulii(dc01, m_dx20);
it[ 0] = (c0<<16) - ((dcdx*m_x0 + dcdy*m_y0)>>4);
it[ 1] = dcdx;
it[ 2] = dcdy;
}
#if defined(__arm__) && !defined(__thumb__)
inline void compute_iterators_t::iterators0032(int32_t* it,
int32_t c0, int32_t c1, int32_t c2) const
{
::iterators0032(this, it, c0, c1, c2);
}
#else
void compute_iterators_t::iterators0032(int32_t* it,
int32_t c0, int32_t c1, int32_t c2) const
{
int64_t it64[3];
iterators0032(it64, c0, c1, c2);
it[0] = it64[0];
it[1] = it64[1];
it[2] = it64[2];
}
#endif
// ----------------------------------------------------------------------------
static inline int32_t clampZ(GLfixed z) CONST;
int32_t clampZ(GLfixed z) {
z = (z & ~(z>>31));
if (z >= 0x10000)
z = 0xFFFF;
return z;
}
static __attribute__((noinline))
void fetch_texcoord_impl(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
vertex_t* const vtx[3] = { v0, v1, v2 };
array_t const * const texcoordArray = c->arrays.texture;
for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; i++) {
if (!(c->rasterizer.state.texture[i].enable))
continue;
for (int j=0 ; j<3 ; j++) {
vertex_t* const v = vtx[j];
if (v->flags & vertex_t::TT)
continue;
// NOTE: here we could compute automatic texgen
// such as sphere/cube maps, instead of fetching them
// from the textcoord array.
vec4_t& coords = v->texture[i];
const GLubyte* tp = texcoordArray[i].element(
v->index & vertex_cache_t::INDEX_MASK);
texcoordArray[i].fetch(c, coords.v, tp);
// transform texture coordinates...
coords.Q = 0x10000;
const transform_t& tr = c->transforms.texture[i].transform;
if (ggl_unlikely(tr.ops)) {
c->arrays.tex_transform[i](&tr, &coords, &coords);
}
// divide by Q
const GGLfixed q = coords.Q;
if (ggl_unlikely(q != 0x10000)) {
const int32_t qinv = gglRecip28(q);
coords.S = gglMulx(coords.S, qinv, 28);
coords.T = gglMulx(coords.T, qinv, 28);
}
}
}
v0->flags |= vertex_t::TT;
v1->flags |= vertex_t::TT;
v2->flags |= vertex_t::TT;
}
inline void fetch_texcoord(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
const uint32_t enables = c->rasterizer.state.enables;
if (!(enables & GGL_ENABLE_TMUS))
return;
// Fetch & transform texture coordinates...
if (ggl_likely(v0->flags & v1->flags & v2->flags & vertex_t::TT)) {
// already done for all three vertices, bail...
return;
}
fetch_texcoord_impl(c, v0, v1, v2);
}
// ----------------------------------------------------------------------------
#if 0
#pragma mark -
#pragma mark Point
#endif
void primitive_nop_point(ogles_context_t*, vertex_t*) {
}
void primitive_point(ogles_context_t* c, vertex_t* v)
{
// lighting & clamping...
const uint32_t enables = c->rasterizer.state.enables;
if (ggl_unlikely(!(v->flags & vertex_t::LIT))) {
if (c->lighting.enable) {
c->lighting.lightVertex(c, v);
} else {
v->flags |= vertex_t::LIT;
const GLvoid* cp = c->arrays.color.element(
v->index & vertex_cache_t::INDEX_MASK);
c->arrays.color.fetch(c, v->color.v, cp);
}
if (enables & GGL_ENABLE_FOG) {
v->fog = c->fog.fog(c, v->eye.z);
}
}
// XXX: we don't need to do that each-time
// if color array and lighting not enabled
c->rasterizer.procs.color4xv(c, v->color.v);
// XXX: look into ES point-sprite extension
if (enables & GGL_ENABLE_TMUS) {
fetch_texcoord(c, v,v,v);
for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; i++) {
if (!c->rasterizer.state.texture[i].enable)
continue;
int32_t itt[8];
itt[1] = itt[2] = itt[4] = itt[5] = 0;
itt[6] = itt[7] = 16; // XXX: check that
if (c->rasterizer.state.texture[i].s_wrap == GGL_CLAMP) {
int width = c->textures.tmu[i].texture->surface.width;
itt[0] = v->texture[i].S * width;
itt[6] = 0;
}
if (c->rasterizer.state.texture[i].t_wrap == GGL_CLAMP) {
int height = c->textures.tmu[i].texture->surface.height;
itt[3] = v->texture[i].T * height;
itt[7] = 0;
}
c->rasterizer.procs.texCoordGradScale8xv(c, i, itt);
}
}
if (enables & GGL_ENABLE_DEPTH_TEST) {
int32_t itz[3];
itz[0] = clampZ(v->window.z) * 0x00010001;
itz[1] = itz[2] = 0;
c->rasterizer.procs.zGrad3xv(c, itz);
}
if (enables & GGL_ENABLE_FOG) {
GLfixed itf[3];
itf[0] = v->fog;
itf[1] = itf[2] = 0;
c->rasterizer.procs.fogGrad3xv(c, itf);
}
// Render our point...
c->rasterizer.procs.pointx(c, v->window.v, c->point.size);
}
// ----------------------------------------------------------------------------
#if 0
#pragma mark -
#pragma mark Line
#endif
void primitive_nop_line(ogles_context_t*, vertex_t*, vertex_t*) {
}
void primitive_line(ogles_context_t* c, vertex_t* v0, vertex_t* v1)
{
// get texture coordinates
fetch_texcoord(c, v0, v1, v1);
// light/shade the vertices first (they're copied below)
c->lighting.lightTriangle(c, v0, v1, v1);
// clip the line if needed
if (ggl_unlikely((v0->flags | v1->flags) & vertex_t::CLIP_ALL)) {
unsigned int count = clip_line(c, v0, v1);
if (ggl_unlikely(count == 0))
return;
}
// compute iterators...
const uint32_t enables = c->rasterizer.state.enables;
const uint32_t mask = GGL_ENABLE_TMUS |
GGL_ENABLE_SMOOTH |
GGL_ENABLE_W |
GGL_ENABLE_FOG |
GGL_ENABLE_DEPTH_TEST;
if (ggl_unlikely(enables & mask)) {
c->lerp.initLine(v0, v1);
lerp_triangle(c, v0, v1, v0);
}
// render our line
c->rasterizer.procs.linex(c, v0->window.v, v1->window.v, c->line.width);
}
// ----------------------------------------------------------------------------
#if 0
#pragma mark -
#pragma mark Triangle
#endif
void primitive_nop_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2) {
}
void primitive_clip_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
uint32_t cc = (v0->flags | v1->flags | v2->flags) & vertex_t::CLIP_ALL;
if (ggl_likely(!cc)) {
// code below must be as optimized as possible, this is the
// common code path.
// This triangle is not clipped, test if it's culled
// unclipped triangle...
c->lerp.initTriangle(v0, v1, v2);
if (cull_triangle(c, v0, v1, v2))
return; // culled!
// Fetch all texture coordinates if needed
fetch_texcoord(c, v0, v1, v2);
// light (or shade) our triangle!
c->lighting.lightTriangle(c, v0, v1, v2);
triangle(c, v0, v1, v2);
return;
}
// The assumption here is that we're not going to clip very often,
// and even more rarely will we clip a triangle that ends up
// being culled out. So it's okay to light the vertices here, even though
// in a few cases we won't render the triangle (if culled).
// Fetch texture coordinates...
fetch_texcoord(c, v0, v1, v2);
// light (or shade) our triangle!
c->lighting.lightTriangle(c, v0, v1, v2);
clip_triangle(c, v0, v1, v2);
}
// -----------------------------------------------------------------------
void triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
// compute iterators...
const uint32_t enables = c->rasterizer.state.enables;
const uint32_t mask = GGL_ENABLE_TMUS |
GGL_ENABLE_SMOOTH |
GGL_ENABLE_W |
GGL_ENABLE_FOG |
GGL_ENABLE_DEPTH_TEST;
if (ggl_likely(enables & mask))
lerp_triangle(c, v0, v1, v2);
c->rasterizer.procs.trianglex(c, v0->window.v, v1->window.v, v2->window.v);
}
void lerp_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
const uint32_t enables = c->rasterizer.state.enables;
c->lerp.initLerp(v0, enables);
// set up texture iterators
if (enables & GGL_ENABLE_TMUS) {
if (enables & GGL_ENABLE_W) {
lerp_texcoords_w(c, v0, v1, v2);
} else {
lerp_texcoords(c, v0, v1, v2);
}
}
// set up the color iterators
const compute_iterators_t& lerp = c->lerp;
if (enables & GGL_ENABLE_SMOOTH) {
GLfixed itc[12];
for (int i=0 ; i<4 ; i++) {
const GGLcolor c0 = v0->color.v[i] * 255;
const GGLcolor c1 = v1->color.v[i] * 255;
const GGLcolor c2 = v2->color.v[i] * 255;
lerp.iterators1616(&itc[i*3], c0, c1, c2);
}
c->rasterizer.procs.colorGrad12xv(c, itc);
}
if (enables & GGL_ENABLE_DEPTH_TEST) {
int32_t itz[3];
const int32_t v0z = clampZ(v0->window.z);
const int32_t v1z = clampZ(v1->window.z);
const int32_t v2z = clampZ(v2->window.z);
if (ggl_unlikely(c->polygonOffset.enable)) {
const int32_t units = (c->polygonOffset.units << 16);
const GLfixed factor = c->polygonOffset.factor;
if (factor) {
int64_t itz64[3];
lerp.iterators0032(itz64, v0z, v1z, v2z);
int64_t maxDepthSlope = max(itz64[1], itz64[2]);
itz[0] = uint32_t(itz64[0])
+ uint32_t((maxDepthSlope*factor)>>16) + units;
itz[1] = uint32_t(itz64[1]);
itz[2] = uint32_t(itz64[2]);
} else {
lerp.iterators0032(itz, v0z, v1z, v2z);
itz[0] += units;
}
} else {
lerp.iterators0032(itz, v0z, v1z, v2z);
}
c->rasterizer.procs.zGrad3xv(c, itz);
}
if (ggl_unlikely(enables & GGL_ENABLE_FOG)) {
GLfixed itf[3];
lerp.iterators1616(itf, v0->fog, v1->fog, v2->fog);
c->rasterizer.procs.fogGrad3xv(c, itf);
}
}
static inline
int compute_lod(ogles_context_t* c, int i,
int32_t s0, int32_t t0, int32_t s1, int32_t t1, int32_t s2, int32_t t2)
{
// Compute mipmap level / primitive
// rho = sqrt( texelArea / area )
// lod = log2( rho )
// lod = log2( texelArea / area ) / 2
// lod = (log2( texelArea ) - log2( area )) / 2
const compute_iterators_t& lerp = c->lerp;
const GGLcoord area = abs(lerp.area());
const int w = c->textures.tmu[i].texture->surface.width;
const int h = c->textures.tmu[i].texture->surface.height;
const int shift = 16 + (16 - TRI_FRACTION_BITS);
int32_t texelArea = abs( gglMulx(s1-s0, t2-t0, shift) -
gglMulx(s2-s0, t1-t0, shift) )*w*h;
int log2TArea = (32-TRI_FRACTION_BITS -1) - gglClz(texelArea);
int log2Area = (32-TRI_FRACTION_BITS*2-1) - gglClz(area);
int lod = (log2TArea - log2Area + 1) >> 1;
return lod;
}
void lerp_texcoords(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
const compute_iterators_t& lerp = c->lerp;
int32_t itt[8] __attribute__((aligned(16)));
for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; i++) {
const texture_t& tmu = c->rasterizer.state.texture[i];
if (!tmu.enable)
continue;
// compute the jacobians using block floating-point
int32_t s0 = v0->texture[i].S;
int32_t t0 = v0->texture[i].T;
int32_t s1 = v1->texture[i].S;
int32_t t1 = v1->texture[i].T;
int32_t s2 = v2->texture[i].S;
int32_t t2 = v2->texture[i].T;
const GLenum min_filter = c->textures.tmu[i].texture->min_filter;
if (ggl_unlikely(min_filter >= GL_NEAREST_MIPMAP_NEAREST)) {
int lod = compute_lod(c, i, s0, t0, s1, t1, s2, t2);
c->rasterizer.procs.bindTextureLod(c, i,
&c->textures.tmu[i].texture->mip(lod));
}
// premultiply (s,t) when clampling
if (tmu.s_wrap == GGL_CLAMP) {
const int width = tmu.surface.width;
s0 *= width;
s1 *= width;
s2 *= width;
}
if (tmu.t_wrap == GGL_CLAMP) {
const int height = tmu.surface.height;
t0 *= height;
t1 *= height;
t2 *= height;
}
itt[6] = -lerp.iteratorsScale(itt+0, s0, s1, s2);
itt[7] = -lerp.iteratorsScale(itt+3, t0, t1, t2);
c->rasterizer.procs.texCoordGradScale8xv(c, i, itt);
}
}
void lerp_texcoords_w(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
const compute_iterators_t& lerp = c->lerp;
int32_t itt[8] __attribute__((aligned(16)));
int32_t itw[3];
// compute W's scale to 2.30
int32_t w0 = v0->window.w;
int32_t w1 = v1->window.w;
int32_t w2 = v2->window.w;
int wscale = 32 - gglClz(w0|w1|w2);
// compute the jacobian using block floating-point
int sc = lerp.iteratorsScale(itw, w0, w1, w2);
sc += wscale - 16;
c->rasterizer.procs.wGrad3xv(c, itw);
for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; i++) {
const texture_t& tmu = c->rasterizer.state.texture[i];
if (!tmu.enable)
continue;
// compute the jacobians using block floating-point
int32_t s0 = v0->texture[i].S;
int32_t t0 = v0->texture[i].T;
int32_t s1 = v1->texture[i].S;
int32_t t1 = v1->texture[i].T;
int32_t s2 = v2->texture[i].S;
int32_t t2 = v2->texture[i].T;
const GLenum min_filter = c->textures.tmu[i].texture->min_filter;
if (ggl_unlikely(min_filter >= GL_NEAREST_MIPMAP_NEAREST)) {
int lod = compute_lod(c, i, s0, t0, s1, t1, s2, t2);
c->rasterizer.procs.bindTextureLod(c, i,
&c->textures.tmu[i].texture->mip(lod));
}
// premultiply (s,t) when clampling
if (tmu.s_wrap == GGL_CLAMP) {
const int width = tmu.surface.width;
s0 *= width;
s1 *= width;
s2 *= width;
}
if (tmu.t_wrap == GGL_CLAMP) {
const int height = tmu.surface.height;
t0 *= height;
t1 *= height;
t2 *= height;
}
s0 = gglMulx(s0, w0, wscale);
t0 = gglMulx(t0, w0, wscale);
s1 = gglMulx(s1, w1, wscale);
t1 = gglMulx(t1, w1, wscale);
s2 = gglMulx(s2, w2, wscale);
t2 = gglMulx(t2, w2, wscale);
itt[6] = sc - lerp.iteratorsScale(itt+0, s0, s1, s2);
itt[7] = sc - lerp.iteratorsScale(itt+3, t0, t1, t2);
c->rasterizer.procs.texCoordGradScale8xv(c, i, itt);
}
}
static inline
bool cull_triangle(ogles_context_t* c, vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
if (ggl_likely(c->cull.enable)) {
const GLenum winding = (c->lerp.area() > 0) ? GL_CW : GL_CCW;
const GLenum face = (winding == c->cull.frontFace) ? GL_FRONT : GL_BACK;
if (face == c->cull.cullFace)
return true; // culled!
}
return false;
}
static inline
GLfixed frustumPlaneDist(int plane, const vec4_t& s)
{
const GLfixed d = s.v[ plane >> 1 ];
return ((plane & 1) ? (s.w - d) : (s.w + d));
}
static inline
int32_t clipDivide(GLfixed a, GLfixed b) {
// returns a 4.28 fixed-point
return gglMulDivi(1LU<<28, a, b);
}
void clip_triangle(ogles_context_t* c,
vertex_t* v0, vertex_t* v1, vertex_t* v2)
{
uint32_t all_cc = (v0->flags | v1->flags | v2->flags) & vertex_t::CLIP_ALL;
vertex_t *p0, *p1, *p2;
const int MAX_CLIPPING_PLANES = 6 + OGLES_MAX_CLIP_PLANES;
const int MAX_VERTICES = 3;
// Temporary buffer to hold the new vertices. Each plane can add up to
// two new vertices (because the polygon is convex).
// We need one extra element, to handle an overflow case when
// the polygon degenerates into something non convex.
vertex_t buffer[MAX_CLIPPING_PLANES * 2 + 1]; // ~3KB
vertex_t* buf = buffer;
// original list of vertices (polygon to clip, in fact this
// function works with an arbitrary polygon).
vertex_t* in[3] = { v0, v1, v2 };
// output lists (we need 2, which we use back and forth)
// (maximum outpout list's size is MAX_CLIPPING_PLANES + MAX_VERTICES)
// 2 more elements for overflow when non convex polygons.
vertex_t* out[2][MAX_CLIPPING_PLANES + MAX_VERTICES + 2];
unsigned int outi = 0;
// current input list
vertex_t** ivl = in;
// 3 input vertices, 0 in the output list, first plane
unsigned int ic = 3;
// User clip-planes first, the clipping is always done in eye-coordinate
// this is basically the same algorithm than for the view-volume
// clipping, except for the computation of the distance (vertex, plane)
// and the fact that we need to compute the eye-coordinates of each
// new vertex we create.
if (ggl_unlikely(all_cc & vertex_t::USER_CLIP_ALL))
{
unsigned int plane = 0;
uint32_t cc = (all_cc & vertex_t::USER_CLIP_ALL) >> 8;
do {
if (cc & 1) {
// pointers to our output list (head and current)
vertex_t** const ovl = &out[outi][0];
vertex_t** output = ovl;
unsigned int oc = 0;
unsigned int sentinel = 0;
// previous vertex, compute distance to the plane
vertex_t* s = ivl[ic-1];
const vec4_t& equation = c->clipPlanes.plane[plane].equation;
GLfixed sd = dot4(equation.v, s->eye.v);
// clip each vertex against this plane...
for (unsigned int i=0 ; i<ic ; i++) {
vertex_t* p = ivl[i];
const GLfixed pd = dot4(equation.v, p->eye.v);
if (sd >= 0) {
if (pd >= 0) {
// both inside
*output++ = p;
oc++;
} else {
// s inside, p outside (exiting)
const GLfixed t = clipDivide(sd, sd-pd);
c->arrays.clipEye(c, buf, t, p, s);
*output++ = buf++;
oc++;
if (++sentinel >= 3)
return; // non-convex polygon!
}
} else {
if (pd >= 0) {
// s outside (entering)
if (pd) {
const GLfixed t = clipDivide(pd, pd-sd);
c->arrays.clipEye(c, buf, t, s, p);
*output++ = buf++;
oc++;
if (++sentinel >= 3)
return; // non-convex polygon!
}
*output++ = p;
oc++;
} else {
// both outside
}
}
s = p;
sd = pd;
}
// output list become the new input list
if (oc<3)
return; // less than 3 vertices left? we're done!
ivl = ovl;
ic = oc;
outi = 1-outi;
}
cc >>= 1;
plane++;
} while (cc);
}
// frustum clip-planes
if (all_cc & vertex_t::FRUSTUM_CLIP_ALL)
{
unsigned int plane = 0;
uint32_t cc = all_cc & vertex_t::FRUSTUM_CLIP_ALL;
do {
if (cc & 1) {
// pointers to our output list (head and current)
vertex_t** const ovl = &out[outi][0];
vertex_t** output = ovl;
unsigned int oc = 0;
unsigned int sentinel = 0;
// previous vertex, compute distance to the plane
vertex_t* s = ivl[ic-1];
GLfixed sd = frustumPlaneDist(plane, s->clip);
// clip each vertex against this plane...
for (unsigned int i=0 ; i<ic ; i++) {
vertex_t* p = ivl[i];
const GLfixed pd = frustumPlaneDist(plane, p->clip);
if (sd >= 0) {
if (pd >= 0) {
// both inside
*output++ = p;
oc++;
} else {
// s inside, p outside (exiting)
const GLfixed t = clipDivide(sd, sd-pd);
c->arrays.clipVertex(c, buf, t, p, s);
*output++ = buf++;
oc++;
if (++sentinel >= 3)
return; // non-convex polygon!
}
} else {
if (pd >= 0) {
// s outside (entering)
if (pd) {
const GLfixed t = clipDivide(pd, pd-sd);
c->arrays.clipVertex(c, buf, t, s, p);
*output++ = buf++;
oc++;
if (++sentinel >= 3)
return; // non-convex polygon!
}
*output++ = p;
oc++;
} else {
// both outside
}
}
s = p;
sd = pd;
}
// output list become the new input list
if (oc<3)
return; // less than 3 vertices left? we're done!
ivl = ovl;
ic = oc;
outi = 1-outi;
}
cc >>= 1;
plane++;
} while (cc);
}
// finally we can render our triangles...
p0 = ivl[0];
p1 = ivl[1];
for (unsigned int i=2 ; i<ic ; i++) {
p2 = ivl[i];
c->lerp.initTriangle(p0, p1, p2);
if (cull_triangle(c, p0, p1, p2)) {
p1 = p2;
continue; // culled!
}
triangle(c, p0, p1, p2);
p1 = p2;
}
}
unsigned int clip_line(ogles_context_t* c, vertex_t* s, vertex_t* p)
{
const uint32_t all_cc = (s->flags | p->flags) & vertex_t::CLIP_ALL;
if (ggl_unlikely(all_cc & vertex_t::USER_CLIP_ALL))
{
unsigned int plane = 0;
uint32_t cc = (all_cc & vertex_t::USER_CLIP_ALL) >> 8;
do {
if (cc & 1) {
const vec4_t& equation = c->clipPlanes.plane[plane].equation;
const GLfixed sd = dot4(equation.v, s->eye.v);
const GLfixed pd = dot4(equation.v, p->eye.v);
if (sd >= 0) {
if (pd >= 0) {
// both inside
} else {
// s inside, p outside (exiting)
const GLfixed t = clipDivide(sd, sd-pd);
c->arrays.clipEye(c, p, t, p, s);
}
} else {
if (pd >= 0) {
// s outside (entering)
if (pd) {
const GLfixed t = clipDivide(pd, pd-sd);
c->arrays.clipEye(c, s, t, s, p);
}
} else {
// both outside
return 0;
}
}
}
cc >>= 1;
plane++;
} while (cc);
}
// frustum clip-planes
if (all_cc & vertex_t::FRUSTUM_CLIP_ALL)
{
unsigned int plane = 0;
uint32_t cc = all_cc & vertex_t::FRUSTUM_CLIP_ALL;
do {
if (cc & 1) {
const GLfixed sd = frustumPlaneDist(plane, s->clip);
const GLfixed pd = frustumPlaneDist(plane, p->clip);
if (sd >= 0) {
if (pd >= 0) {
// both inside
} else {
// s inside, p outside (exiting)
const GLfixed t = clipDivide(sd, sd-pd);
c->arrays.clipVertex(c, p, t, p, s);
}
} else {
if (pd >= 0) {
// s outside (entering)
if (pd) {
const GLfixed t = clipDivide(pd, pd-sd);
c->arrays.clipVertex(c, s, t, s, p);
}
} else {
// both outside
return 0;
}
}
}
cc >>= 1;
plane++;
} while (cc);
}
return 2;
}
}; // namespace android