/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrGLConfig_DEFINED
#define GrGLConfig_DEFINED
#include "GrTypes.h"
/**
* Optional GL config file.
*/
#ifdef GR_GL_CUSTOM_SETUP_HEADER
#include GR_GL_CUSTOM_SETUP_HEADER
#endif
#if !defined(GR_GL_FUNCTION_TYPE)
#define GR_GL_FUNCTION_TYPE
#endif
/**
* The following are optional defines that can be enabled at the compiler
* command line, in a IDE project, in a GrUserConfig.h file, or in a GL custom
* file (if one is in use). If a GR_GL_CUSTOM_SETUP_HEADER is used they can
* also be placed there.
*
* GR_GL_LOG_CALLS: if 1 Gr can print every GL call using GrPrintf. Defaults to
* 0. Logging can be enabled and disabled at runtime using a debugger via to
* global gLogCallsGL. The initial value of gLogCallsGL is controlled by
* GR_GL_LOG_CALLS_START.
*
* GR_GL_LOG_CALLS_START: controls the initial value of gLogCallsGL when
* GR_GL_LOG_CALLS is 1. Defaults to 0.
*
* GR_GL_CHECK_ERROR: if enabled Gr can do a glGetError() after every GL call.
* Defaults to 1 if SK_DEBUG is set, otherwise 0. When GR_GL_CHECK_ERROR is 1
* this can be toggled in a debugger using the gCheckErrorGL global. The initial
* value of gCheckErrorGL is controlled by by GR_GL_CHECK_ERROR_START.
*
* GR_GL_CHECK_ERROR_START: controls the initial value of gCheckErrorGL
* when GR_GL_CHECK_ERROR is 1. Defaults to 1.
*
* GR_GL_NO_CONSTANT_ATTRIBUTES: if this evaluates to true then the GL backend
* will use uniforms instead of attributes in all cases when there is not
* per-vertex data. This is important when the underlying GL implementation
* doesn't actually support immediate style attribute values (e.g. when
* the GL stream is converted to DX as in ANGLE on Chrome). Defaults to 0.
*
* GR_GL_USE_BUFFER_DATA_NULL_HINT: When specifing new data for a vertex/index
* buffer that replaces old data Ganesh can give a hint to the driver that the
* previous data will not be used in future draws like this:
* glBufferData(GL_..._BUFFER, size, NULL, usage); //<--hint, NULL means
* glBufferSubData(GL_..._BUFFER, 0, lessThanSize, data) // old data can't be
* // used again.
* However, this can be an unoptimization on some platforms, esp. Chrome.
* Chrome's cmd buffer will create a new allocation and memset the whole thing
* to zero (for security reasons). Defaults to 1 (enabled).
*
* GR_GL_PER_GL_FUNC_CALLBACK: When set to 1 the GrGLInterface object provides
* a function pointer that is called just before every gl function. The ptr must
* be valid (i.e. there is no NULL check). However, by default the callback will
* be set to a function that does nothing. The signature of the function is:
* void function(const GrGLInterface*)
* It is not extern "C".
* The GrGLInterface field fCallback specifies the function ptr and there is an
* additional field fCallbackData of type intptr_t for client data.
*
* GR_GL_RGBA_8888_PIXEL_OPS_SLOW: Set this to 1 if it is known that performing
* glReadPixels / glTex(Sub)Image with format=GL_RGBA, type=GL_UNISIGNED_BYTE is
* significantly slower than format=GL_BGRA, type=GL_UNISIGNED_BYTE.
*
* GR_GL_FULL_READPIXELS_FASTER_THAN_PARTIAL: Set this to 1 if calling
* glReadPixels to read the entire framebuffer is faster than calling it with
* the same sized rectangle but with a framebuffer bound that is larger than
* the rectangle read.
*
* GR_GL_CHECK_ALLOC_WITH_GET_ERROR: If set to 1 this will then glTexImage,
* glBufferData, glRenderbufferStorage, etc will be checked for errors. This
* amounts to ensuring the error is GL_NO_ERROR, calling the allocating
* function, and then checking that the error is still GL_NO_ERROR. When the
* value is 0 we will assume no error was generated without checking.
*
* GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT: We will normally check the FBO status
* every time we bind a texture or renderbuffer to an FBO. However, in some
* environments CheckFrameBufferStatus is very expensive. If this is set we will
* check the first time we use a color format or a combination of color /
* stencil formats as attachments. If the FBO is complete we will assume
* subsequent attachments with the same formats are complete as well.
*
* GR_GL_USE_NV_PATH_RENDERING: Enable experimental support for
* GL_NV_path_rendering. There are known issues with clipping, non-AA paths, and
* perspective.
*
* GR_GL_MUST_USE_VBO: Indicates that all vertices and indices must be rendered
* from VBOs. Chromium's command buffer doesn't allow glVertexAttribArray with
* ARARY_BUFFER 0 bound or glDrawElements with ELEMENT_ARRAY_BUFFER 0 bound.
*
* GR_GL_USE_NEW_SHADER_SOURCE_SIGNATURE is for compatibility with the new version
* of the OpenGLES2.0 headers from Khronos. glShaderSource now takes a const char * const *,
* instead of a const char
*/
#if !defined(GR_GL_LOG_CALLS)
#ifdef SK_DEBUG
#define GR_GL_LOG_CALLS 1
#else
#define GR_GL_LOG_CALLS 0
#endif
#endif
#if !defined(GR_GL_LOG_CALLS_START)
#define GR_GL_LOG_CALLS_START 0
#endif
#if !defined(GR_GL_CHECK_ERROR)
#ifdef SK_DEBUG
#define GR_GL_CHECK_ERROR 1
#else
#define GR_GL_CHECK_ERROR 0
#endif
#endif
#if !defined(GR_GL_CHECK_ERROR_START)
#define GR_GL_CHECK_ERROR_START 1
#endif
#if !defined(GR_GL_NO_CONSTANT_ATTRIBUTES)
#define GR_GL_NO_CONSTANT_ATTRIBUTES 0
#endif
#if !defined(GR_GL_USE_BUFFER_DATA_NULL_HINT)
#define GR_GL_USE_BUFFER_DATA_NULL_HINT 1
#endif
#if !defined(GR_GL_PER_GL_FUNC_CALLBACK)
#define GR_GL_PER_GL_FUNC_CALLBACK 0
#endif
#if !defined(GR_GL_RGBA_8888_PIXEL_OPS_SLOW)
#define GR_GL_RGBA_8888_PIXEL_OPS_SLOW 0
#endif
#if !defined(GR_GL_FULL_READPIXELS_FASTER_THAN_PARTIAL)
#define GR_GL_FULL_READPIXELS_FASTER_THAN_PARTIAL 0
#endif
#if !defined(GR_GL_CHECK_ALLOC_WITH_GET_ERROR)
#define GR_GL_CHECK_ALLOC_WITH_GET_ERROR 1
#endif
#if !defined(GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT)
#define GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT 0
#endif
#if !defined(GR_GL_USE_NV_PATH_RENDERING)
#define GR_GL_USE_NV_PATH_RENDERING 0
#endif
#if !defined(GR_GL_MUST_USE_VBO)
#define GR_GL_MUST_USE_VBO 0
#endif
#if !defined(GR_GL_USE_NEW_SHADER_SOURCE_SIGNATURE)
#define GR_GL_USE_NEW_SHADER_SOURCE_SIGNATURE 0
#endif
// We now have a separate GrGLInterface function pointer entry for the IMG/EXT version of
// glRenderbufferStorageMultisampled. However, Chrome is setting the one we now use for
// ES3 MSAA to point to the IMG/EXT function. This macro exists to make Skia ignore the
// ES3 MSAA and instead use the IMG/EXT version with the old function pointer entry. It will
// be removed as soon as Chrome is updated to set the new function pointer.
#if !defined(GR_GL_IGNORE_ES3_MSAA)
#define GR_GL_IGNORE_ES3_MSAA 0
#endif
/**
* There is a strange bug that occurs on Macs with NVIDIA GPUs. We don't
* fully understand it. When (element) array buffers are continually
* respecified using glBufferData performance can fall off of a cliff. The
* driver winds up performing many DMA mapping / unmappings and chews up ~50% of
* the core. However, it has been observed that occaisonally respecifiying the
* buffer using glBufferData and then writing data using glBufferSubData
* prevents the bad behavior.
*
* There is a lot of uncertainty around this issue. In Chrome backgrounding
* the tab somehow initiates this behavior and we don't know what the connection
* is. Another observation is that Chrome's cmd buffer server will actually
* create a buffer full of zeros when it sees a NULL data param (for security
* reasons). If this is disabled and NULL is actually passed all the way to the
* driver then the workaround doesn't help.
*
* The issue is tracked at:
* http://code.google.com/p/chromium/issues/detail?id=114865
*
* When the workaround is enabled we will use the glBufferData / glBufferSubData
* trick every 128 array buffer uploads.
*
* Hopefully we will understand this better and have a cleaner fix or get a
* OS/driver level fix.
*/
#define GR_GL_MAC_BUFFER_OBJECT_PERFOMANCE_WORKAROUND \
(defined(SK_BUILD_FOR_MAC) && \
!GR_GL_USE_BUFFER_DATA_NULL_HINT)
#endif