1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10
11#ifndef GrGLConfig_DEFINED
12#define GrGLConfig_DEFINED
13
14#include "GrTypes.h"
15
16/**
17 * Optional GL config file.
18 */
19#ifdef GR_GL_CUSTOM_SETUP_HEADER
20    #include GR_GL_CUSTOM_SETUP_HEADER
21#endif
22
23#if !defined(GR_GL_FUNCTION_TYPE)
24    #define GR_GL_FUNCTION_TYPE
25#endif
26
27/**
28 * The following are optional defines that can be enabled at the compiler
29 * command line, in a IDE project, in a GrUserConfig.h file, or in a GL custom
30 * file (if one is in use). If a GR_GL_CUSTOM_SETUP_HEADER is used they can
31 * also be placed there.
32 *
33 * GR_GL_LOG_CALLS: if 1 Gr can print every GL call using GrPrintf. Defaults to
34 * 0. Logging can be enabled and disabled at runtime using a debugger via to
35 * global gLogCallsGL. The initial value of gLogCallsGL is controlled by
36 * GR_GL_LOG_CALLS_START.
37 *
38 * GR_GL_LOG_CALLS_START: controls the initial value of gLogCallsGL when
39 * GR_GL_LOG_CALLS is 1. Defaults to 0.
40 *
41 * GR_GL_CHECK_ERROR: if enabled Gr can do a glGetError() after every GL call.
42 * Defaults to 1 if SK_DEBUG is set, otherwise 0. When GR_GL_CHECK_ERROR is 1
43 * this can be toggled in a debugger using the gCheckErrorGL global. The initial
44 * value of gCheckErrorGL is controlled by by GR_GL_CHECK_ERROR_START.
45 *
46 * GR_GL_CHECK_ERROR_START: controls the initial value of gCheckErrorGL
47 * when GR_GL_CHECK_ERROR is 1.  Defaults to 1.
48 *
49 * GR_GL_NO_CONSTANT_ATTRIBUTES: if this evaluates to true then the GL backend
50 * will use uniforms instead of attributes in all cases when there is not
51 * per-vertex data. This is important when the underlying GL implementation
52 * doesn't actually support immediate style attribute values (e.g. when
53 * the GL stream is converted to DX as in ANGLE on Chrome). Defaults to 0.
54 *
55 * GR_GL_USE_BUFFER_DATA_NULL_HINT: When specifing new data for a vertex/index
56 * buffer that replaces old data Ganesh can give a hint to the driver that the
57 * previous data will not be used in future draws like this:
58 *  glBufferData(GL_..._BUFFER, size, NULL, usage);       //<--hint, NULL means
59 *  glBufferSubData(GL_..._BUFFER, 0, lessThanSize, data) //   old data can't be
60 *                                                        //   used again.
61 * However, this can be an unoptimization on some platforms, esp. Chrome.
62 * Chrome's cmd buffer will create a new allocation and memset the whole thing
63 * to zero (for security reasons). Defaults to 1 (enabled).
64 *
65 * GR_GL_PER_GL_FUNC_CALLBACK: When set to 1 the GrGLInterface object provides
66 * a function pointer that is called just before every gl function. The ptr must
67 * be valid (i.e. there is no NULL check). However, by default the callback will
68 * be set to a function that does nothing. The signature of the function is:
69 *    void function(const GrGLInterface*)
70 * It is not extern "C".
71 * The GrGLInterface field fCallback specifies the function ptr and there is an
72 * additional field fCallbackData of type intptr_t for client data.
73 *
74 * GR_GL_RGBA_8888_PIXEL_OPS_SLOW: Set this to 1 if it is known that performing
75 * glReadPixels / glTex(Sub)Image with format=GL_RGBA, type=GL_UNISIGNED_BYTE is
76 * significantly slower than format=GL_BGRA, type=GL_UNISIGNED_BYTE.
77 *
78 * GR_GL_FULL_READPIXELS_FASTER_THAN_PARTIAL: Set this to 1 if calling
79 * glReadPixels to read the entire framebuffer is faster than calling it with
80 * the same sized rectangle but with a framebuffer bound that is larger than
81 * the rectangle read.
82 *
83 * GR_GL_CHECK_ALLOC_WITH_GET_ERROR: If set to 1 this will then glTexImage,
84 * glBufferData, glRenderbufferStorage, etc will be checked for errors. This
85 * amounts to ensuring the error is GL_NO_ERROR, calling the allocating
86 * function, and then checking that the error is still GL_NO_ERROR. When the
87 * value is 0 we will assume no error was generated without checking.
88 *
89 * GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT: We will normally check the FBO status
90 * every time we bind a texture or renderbuffer to an FBO. However, in some
91 * environments CheckFrameBufferStatus is very expensive. If this is set we will
92 * check the first time we use a color format or a combination of color /
93 * stencil formats as attachments. If the FBO is complete we will assume
94 * subsequent attachments with the same formats are complete as well.
95 *
96 * GR_GL_MUST_USE_VBO: Indicates that all vertices and indices must be rendered
97 * from VBOs. Chromium's command buffer doesn't allow glVertexAttribArray with
98 * ARARY_BUFFER 0 bound or glDrawElements with ELEMENT_ARRAY_BUFFER 0 bound.
99 *
100 * GR_GL_USE_NEW_SHADER_SOURCE_SIGNATURE is for compatibility with the new version
101 * of the OpenGLES2.0 headers from Khronos.  glShaderSource now takes a const char * const *,
102 * instead of a const char
103 */
104
105#if !defined(GR_GL_LOG_CALLS)
106    #ifdef SK_DEBUG
107        #define GR_GL_LOG_CALLS 1
108    #else
109        #define GR_GL_LOG_CALLS 0
110    #endif
111#endif
112
113#if !defined(GR_GL_LOG_CALLS_START)
114    #define GR_GL_LOG_CALLS_START                       0
115#endif
116
117#if !defined(GR_GL_CHECK_ERROR)
118    #ifdef SK_DEBUG
119        #define GR_GL_CHECK_ERROR 1
120    #else
121        #define GR_GL_CHECK_ERROR 0
122    #endif
123#endif
124
125#if !defined(GR_GL_CHECK_ERROR_START)
126    #define GR_GL_CHECK_ERROR_START                     1
127#endif
128
129#if !defined(GR_GL_NO_CONSTANT_ATTRIBUTES)
130    #define GR_GL_NO_CONSTANT_ATTRIBUTES                0
131#endif
132
133#if !defined(GR_GL_USE_BUFFER_DATA_NULL_HINT)
134    #define GR_GL_USE_BUFFER_DATA_NULL_HINT             1
135#endif
136
137#if !defined(GR_GL_PER_GL_FUNC_CALLBACK)
138    #define GR_GL_PER_GL_FUNC_CALLBACK                  0
139#endif
140
141#if !defined(GR_GL_RGBA_8888_PIXEL_OPS_SLOW)
142    #define GR_GL_RGBA_8888_PIXEL_OPS_SLOW              0
143#endif
144
145#if !defined(GR_GL_FULL_READPIXELS_FASTER_THAN_PARTIAL)
146    #define GR_GL_FULL_READPIXELS_FASTER_THAN_PARTIAL   0
147#endif
148
149#if !defined(GR_GL_CHECK_ALLOC_WITH_GET_ERROR)
150    #define GR_GL_CHECK_ALLOC_WITH_GET_ERROR            1
151#endif
152
153#if !defined(GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT)
154    #define GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT      0
155#endif
156
157#if !defined(GR_GL_MUST_USE_VBO)
158    #define GR_GL_MUST_USE_VBO                          0
159#endif
160
161#if !defined(GR_GL_USE_NEW_SHADER_SOURCE_SIGNATURE)
162    #define GR_GL_USE_NEW_SHADER_SOURCE_SIGNATURE       0
163#endif
164
165/**
166 * There is a strange bug that occurs on Macs with NVIDIA GPUs. We don't
167 * fully understand it. When (element) array buffers are continually
168 * respecified using glBufferData performance can fall off of a cliff. The
169 * driver winds up performing many DMA mapping / unmappings and chews up ~50% of
170 * the core. However, it has been observed that occaisonally respecifiying the
171 * buffer using glBufferData and then writing data using glBufferSubData
172 * prevents the bad behavior.
173 *
174 * There is a lot of uncertainty around this issue. In Chrome backgrounding
175 * the tab somehow initiates this behavior and we don't know what the connection
176 * is. Another observation is that Chrome's cmd buffer server will actually
177 * create a buffer full of zeros when it sees a NULL data param (for security
178 * reasons). If this is disabled and NULL is actually passed all the way to the
179 * driver then the workaround doesn't help.
180 *
181 * The issue is tracked at:
182 * http://code.google.com/p/chromium/issues/detail?id=114865
183 *
184 * When the workaround is enabled we will use the glBufferData / glBufferSubData
185 * trick every 128 array buffer uploads.
186 *
187 * Hopefully we will understand this better and have a cleaner fix or get a
188 * OS/driver level fix.
189 */
190#define GR_GL_MAC_BUFFER_OBJECT_PERFOMANCE_WORKAROUND   \
191    (defined(SK_BUILD_FOR_MAC) &&                       \
192     !GR_GL_USE_BUFFER_DATA_NULL_HINT)
193
194#endif
195