gpu: Refactor and cleanup CHROMIUM_copy_texture implementation.

gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc

Index: gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
index 5ce4a223fb3d185563e6d8e1948f5b7b4916713b..258f63ef82da36b71abca2f06314ca849807a1a6 100644
--- a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
+++ b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
@@ -10,19 +10,19 @@
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
-#define SHADER0(src) \
-    "#ifdef GL_ES\n"\
-    "precision mediump float;\n"\
-    "#endif\n"\
-    #src
-#define SHADER(src) { false, SHADER0(src), }
-#define SHADER_EXTERNAL_OES0(src) \
-    "#extension GL_OES_EGL_image_external : require\n"\
-    "#ifdef GL_ES\n"\
-    "precision mediump float;\n"\
-    "#endif\n"\
-    #src
-#define SHADER_EXTERNAL_OES(src) { true, SHADER_EXTERNAL_OES0(src), }
+#define SHADER(src)            \
+  "#ifdef GL_ES\n"             \
+  "precision mediump float;\n" \
+  "#endif\n" #src
+#define SHADER_2D(src)              \
+  "#define SamplerType sampler2D\n" \
+  "#define TextureLookup texture2D\n" SHADER(src)
+#define SHADER_EXTERNAL_OES(src)                     \
+  "#extension GL_OES_EGL_image_external : require\n" \
+  "#define SamplerType samplerExternalOES\n"         \
+  "#define TextureLookup texture2D\n" SHADER(src)
+#define SHADERS(src) \
+  { SHADER_2D(src), SHADER_EXTERNAL_OES(src) }
 
 namespace {
 
@@ -31,27 +31,23 @@ const GLfloat kQuadVertices[] = { -1.0f, -1.0f, 0.0f, 1.0f,
                                    1.0f,  1.0f, 0.0f, 1.0f,
                                   -1.0f,  1.0f, 0.0f, 1.0f };

[piman, 2014/04/25 03:30:40]

This should be 2 components per vertex instead of 4... 0, 1 is implied for z, w
if we have vec2's.

[reveman, 2014/04/25 20:27:10]

I'll fix this in a follow up.

 
-enum ProgramId {
-  PROGRAM_COPY_TEXTURE,
-  PROGRAM_COPY_TEXTURE_FLIP_Y,
-  PROGRAM_COPY_TEXTURE_PREMULTIPLY_ALPHA,
-  PROGRAM_COPY_TEXTURE_UNPREMULTIPLY_ALPHA,
-  PROGRAM_COPY_TEXTURE_PREMULTIPLY_ALPHA_FLIPY,
-  PROGRAM_COPY_TEXTURE_UNPREMULTIPLY_ALPHA_FLIPY,
-  PROGRAM_COPY_TEXTURE_OES,
-  PROGRAM_COPY_TEXTURE_OES_FLIP_Y,
-  PROGRAM_COPY_TEXTURE_OES_PREMULTIPLY_ALPHA,
-  PROGRAM_COPY_TEXTURE_OES_UNPREMULTIPLY_ALPHA,
-  PROGRAM_COPY_TEXTURE_OES_PREMULTIPLY_ALPHA_FLIPY,
-  PROGRAM_COPY_TEXTURE_OES_UNPREMULTIPLY_ALPHA_FLIPY,
+enum ShaderId {
+  SHADER_COPY_TEXTURE,
+  SHADER_COPY_TEXTURE_FLIP_Y,

[piman, 2014/04/25 03:30:40]

nit: it'd be nice to be consistent between FLIP_Y and FLIPY.

[reveman, 2014/04/25 20:27:10]

Done.

+  SHADER_COPY_TEXTURE_PREMULTIPLY_ALPHA,
+  SHADER_COPY_TEXTURE_UNPREMULTIPLY_ALPHA,
+  SHADER_COPY_TEXTURE_PREMULTIPLY_ALPHA_FLIPY,
+  SHADER_COPY_TEXTURE_UNPREMULTIPLY_ALPHA_FLIPY,
+  NUM_SHADERS,
 };
 
-struct ShaderInfo {
-  bool needs_egl_image_external;
-  const char* source;
+enum SamplerId {
+  SAMPLER_TEXTURE_2D,
+  SAMPLER_TEXTURE_EXTERNAL_OES,
+  NUM_SAMPLERS,
 };
 
-const ShaderInfo shader_infos[] = {
+const char* vertex_shader_source =
   // VERTEX_SHADER_POS_TEX
   SHADER(
     uniform mat4 u_matrix;
@@ -60,123 +56,64 @@ const ShaderInfo shader_infos[] = {
     void main(void) {
       gl_Position = u_matrix * a_position;
       v_uv = a_position.xy * 0.5 + vec2(0.5, 0.5);
-    }),
+    });
+
+const char* fragment_shader_source[NUM_SHADERS][NUM_SAMPLERS] = {
   // FRAGMENT_SHADER_TEX
-  SHADER(
-    uniform sampler2D u_texSampler;
+  SHADERS(
+    uniform SamplerType u_texSampler;
     varying vec2 v_uv;
     void main(void) {
-      gl_FragColor = texture2D(u_texSampler, v_uv.st);
+      gl_FragColor = TextureLookup(u_texSampler, v_uv.st);
     }),
   // FRAGMENT_SHADER_TEX_FLIP_Y
-  SHADER(
-    uniform sampler2D u_texSampler;
+  SHADERS(
+    uniform SamplerType u_texSampler;
     varying vec2 v_uv;
     void main(void) {
-      gl_FragColor = texture2D(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
+      gl_FragColor = TextureLookup(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));

[piman, 2014/04/25 03:30:40]

Maybe for later... those shaders would be more efficient if we did the uv math
per vertex instead of per pixel (and we do uv math there anyway).

Actually, we could make it a uniform too, to halve the number of shaders.

[reveman, 2014/04/25 20:27:10]

I'll do this in a follow up. I need to change this to support TEXTURE_RECTANGLE
anyhow and I'll make sure to remove all this per-fragment math while at it.

     }),
   // FRAGMENT_SHADER_TEX_PREMULTIPLY_ALPHA
-  SHADER(
-    uniform sampler2D u_texSampler;
+  SHADERS(
+    uniform SamplerType u_texSampler;
     varying vec2 v_uv;
     void main(void) {
-      gl_FragColor = texture2D(u_texSampler, v_uv.st);
+      gl_FragColor = TextureLookup(u_texSampler, v_uv.st);
       gl_FragColor.rgb *= gl_FragColor.a;
     }),
   // FRAGMENT_SHADER_TEX_UNPREMULTIPLY_ALPHA
-  SHADER(
-    uniform sampler2D u_texSampler;
+  SHADERS(
+    uniform SamplerType u_texSampler;
     varying vec2 v_uv;
     void main(void) {
-      gl_FragColor = texture2D(u_texSampler, v_uv.st);
+      gl_FragColor = TextureLookup(u_texSampler, v_uv.st);
       if (gl_FragColor.a > 0.0)
         gl_FragColor.rgb /= gl_FragColor.a;
     }),
   // FRAGMENT_SHADER_TEX_PREMULTIPLY_ALPHA_FLIP_Y
-  SHADER(
-    uniform sampler2D u_texSampler;
+  SHADERS(
+    uniform SamplerType u_texSampler;
     varying vec2 v_uv;
     void main(void) {
-      gl_FragColor = texture2D(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
+      gl_FragColor = TextureLookup(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
       gl_FragColor.rgb *= gl_FragColor.a;
     }),
   // FRAGMENT_SHADER_TEX_UNPREMULTIPLY_ALPHA_FLIP_Y
-  SHADER(
-    uniform sampler2D u_texSampler;
-    varying vec2 v_uv;
-    void main(void) {
-      gl_FragColor = texture2D(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
-      if (gl_FragColor.a > 0.0)
-        gl_FragColor.rgb /= gl_FragColor.a;
-    }),
-  // FRAGMENT_SHADER_TEX_OES
-  SHADER_EXTERNAL_OES(
-    precision mediump float;
-    uniform samplerExternalOES u_texSampler;
+  SHADERS(
+    uniform SamplerType u_texSampler;
     varying vec2 v_uv;
     void main(void) {
-      gl_FragColor = texture2D(u_texSampler, v_uv.st);
-    }),
-  // FRAGMENT_SHADER_TEX_OES_FLIP_Y
-  SHADER_EXTERNAL_OES(
-     precision mediump float;
-     uniform samplerExternalOES u_texSampler;
-     varying vec2 v_uv;
-     void main(void) {
-       gl_FragColor =
-           texture2D(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
-     }),
-  // FRAGMENT_SHADER_TEX_OES_PREMULTIPLY_ALPHA
-  SHADER_EXTERNAL_OES(
-     precision mediump float;
-     uniform samplerExternalOES u_texSampler;
-     varying vec2 v_uv;
-     void main(void) {
-       gl_FragColor = texture2D(u_texSampler, v_uv.st);
-       gl_FragColor.rgb *= gl_FragColor.a;
-     }),
-  // FRAGMENT_SHADER_TEX_OES_UNPREMULTIPLY_ALPHA
-  SHADER_EXTERNAL_OES(
-    precision mediump float;
-    uniform samplerExternalOES u_texSampler;
-    varying vec2 v_uv;
-    void main(void) {
-      gl_FragColor = texture2D(u_texSampler, v_uv.st);
+      gl_FragColor = TextureLookup(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
       if (gl_FragColor.a > 0.0)
         gl_FragColor.rgb /= gl_FragColor.a;
     }),
-  // FRAGMENT_SHADER_TEX_OES_PREMULTIPLY_ALPHA_FLIP_Y
-  SHADER_EXTERNAL_OES(
-      precision mediump float;
-      uniform samplerExternalOES u_texSampler;
-      varying vec2 v_uv;
-      void main(void) {
-        gl_FragColor =
-            texture2D(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
-        gl_FragColor.rgb *= gl_FragColor.a;
-      }),
-  // FRAGMENT_SHADER_TEX_OES_UNPREMULTIPLY_ALPHA_FLIP_Y
-  SHADER_EXTERNAL_OES(
-      precision mediump float;
-      uniform samplerExternalOES u_texSampler;
-      varying vec2 v_uv;
-      void main(void) {
-        gl_FragColor =
-            texture2D(u_texSampler, vec2(v_uv.s, 1.0 - v_uv.t));
-        if (gl_FragColor.a > 0.0)
-          gl_FragColor.rgb /= gl_FragColor.a;
-      }),
 };
 
-const int kNumShaders = arraysize(shader_infos);
-
-// Returns the correct program to evaluate the copy operation for
+// Returns the correct shader id to evaluate the copy operation for
 // the CHROMIUM_flipy and premultiply alpha pixel store settings.
-ProgramId GetProgram(
-    bool flip_y,
-    bool premultiply_alpha,
-    bool unpremultiply_alpha,
-    bool is_source_external_oes) {
+ShaderId GetShaderId(bool flip_y,
+                     bool premultiply_alpha,
+                     bool unpremultiply_alpha) {
   // If both pre-multiply and unpremultiply are requested, then perform no
   // alpha manipulation.
   if (premultiply_alpha && unpremultiply_alpha) {
@@ -187,31 +124,44 @@ ProgramId GetProgram(
   // bit 0: Flip_y
   // bit 1: Premult
   // bit 2: Unpremult
-  // bit 3: External_oes
-  static ProgramId program_ids[] = {
-    PROGRAM_COPY_TEXTURE,
-    PROGRAM_COPY_TEXTURE_FLIP_Y,                         // F
-    PROGRAM_COPY_TEXTURE_PREMULTIPLY_ALPHA,              //   P
-    PROGRAM_COPY_TEXTURE_PREMULTIPLY_ALPHA_FLIPY,        // F P
-    PROGRAM_COPY_TEXTURE_UNPREMULTIPLY_ALPHA,            //     U
-    PROGRAM_COPY_TEXTURE_UNPREMULTIPLY_ALPHA_FLIPY,      // F   U
-    PROGRAM_COPY_TEXTURE,                                //   P U
-    PROGRAM_COPY_TEXTURE,                                // F P U
-    PROGRAM_COPY_TEXTURE_OES,                            //       E
-    PROGRAM_COPY_TEXTURE_OES_FLIP_Y,                     // F     E
-    PROGRAM_COPY_TEXTURE_OES_PREMULTIPLY_ALPHA,          //   P   E
-    PROGRAM_COPY_TEXTURE_OES_PREMULTIPLY_ALPHA_FLIPY,    // F P   E
-    PROGRAM_COPY_TEXTURE_OES_UNPREMULTIPLY_ALPHA,        //     U E
-    PROGRAM_COPY_TEXTURE_OES_UNPREMULTIPLY_ALPHA_FLIPY,  // F   U E
-    PROGRAM_COPY_TEXTURE_OES,                            //   P U E
-    PROGRAM_COPY_TEXTURE_OES,                            // F P U E
+  static ShaderId shader_ids[] = {
+      SHADER_COPY_TEXTURE,
+      SHADER_COPY_TEXTURE_FLIP_Y,                     // F
+      SHADER_COPY_TEXTURE_PREMULTIPLY_ALPHA,          //   P
+      SHADER_COPY_TEXTURE_PREMULTIPLY_ALPHA_FLIPY,    // F P
+      SHADER_COPY_TEXTURE_UNPREMULTIPLY_ALPHA,        //     U
+      SHADER_COPY_TEXTURE_UNPREMULTIPLY_ALPHA_FLIPY,  // F   U
+      SHADER_COPY_TEXTURE,                            //   P U
+      SHADER_COPY_TEXTURE,                            // F P U

[piman, 2014/04/25 03:30:40]

Shouldn't this last one be SHADER_COPY_TEXTURE_FLIP_Y?

[reveman, 2014/04/25 20:27:10]

Sure, I assume these last two are invalid configurations that we never hit but
having the premult and unpremult cancel each other out makes some sense..

   };
 
-  unsigned index = (flip_y                 ? (1 << 0) : 0) |
-                   (premultiply_alpha      ? (1 << 1) : 0) |
-                   (unpremultiply_alpha    ? (1 << 2) : 0) |
-                   (is_source_external_oes ? (1 << 3) : 0);
-  return program_ids[index];
+  unsigned index = (flip_y              ? (1 << 0) : 0) |
+                   (premultiply_alpha   ? (1 << 1) : 0) |
+                   (unpremultiply_alpha ? (1 << 2) : 0);
+  return shader_ids[index];
+}
+
+SamplerId GetSamplerId(GLenum source_target) {
+  switch (source_target) {
+    case GL_TEXTURE_2D:
+      return SAMPLER_TEXTURE_2D;
+    case GL_TEXTURE_EXTERNAL_OES:
+      return SAMPLER_TEXTURE_EXTERNAL_OES;
+  }
+
+  NOTREACHED();
+  return SAMPLER_TEXTURE_2D;
+}
+
+void CompileShader(GLuint shader, const char* shader_source) {
+  glShaderSource(shader, 1, &shader_source, 0);
+  glCompileShader(shader);
+#ifndef NDEBUG
+  GLint compile_status;
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &compile_status);
+  if (GL_TRUE != compile_status)
+    DLOG(ERROR) << "CopyTextureCHROMIUM: shader compilation failure.";
+#endif
 }
 
 }  // namespace
@@ -219,27 +169,17 @@ ProgramId GetProgram(
 namespace gpu {
 
 CopyTextureCHROMIUMResourceManager::CopyTextureCHROMIUMResourceManager()
-  : initialized_(false),
-    buffer_id_(0),
-    framebuffer_(0) {
-  for (int i = 0; i < kNumPrograms; ++i) {
-    programs_[i] = 0;
-    matrix_handle_[i] = 0;
-    sampler_locations_[i] = 0;
-  }
+    : initialized_(false), buffer_id_(0), framebuffer_(0), vertex_shader_(0) {
 }
 
+CopyTextureCHROMIUMResourceManager::~CopyTextureCHROMIUMResourceManager() {}
+
 void CopyTextureCHROMIUMResourceManager::Initialize(
     const gles2::GLES2Decoder* decoder) {
   COMPILE_ASSERT(
       kVertexPositionAttrib == 0u,
       Position_attribs_must_be_0);
 
-  const char* extensions =
-      reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS));
-  bool have_egl_image_external = extensions &&
-      strstr(extensions, "GL_OES_EGL_image_external");
-
   // Initialize all of the GPU resources required to perform the copy.
   glGenBuffersARB(1, &buffer_id_);
   glBindBuffer(GL_ARRAY_BUFFER, buffer_id_);
@@ -248,56 +188,8 @@ void CopyTextureCHROMIUMResourceManager::Initialize(
 
   glGenFramebuffersEXT(1, &framebuffer_);
 
-  // TODO(gman): Init these on demand.
-  GLuint shaders[kNumShaders];
-  for (int shader = 0; shader < kNumShaders; ++shader) {
-    shaders[shader] = glCreateShader(
-        shader == 0 ? GL_VERTEX_SHADER : GL_FRAGMENT_SHADER);
-    const ShaderInfo& info = shader_infos[shader];
-    if (info.needs_egl_image_external && !have_egl_image_external) {
-      continue;
-    }
-    const char* shader_source = shader_infos[shader].source;
-    glShaderSource(shaders[shader], 1, &shader_source, 0);
-    glCompileShader(shaders[shader]);
-#ifndef NDEBUG
-    GLint compile_status;
-    glGetShaderiv(shaders[shader], GL_COMPILE_STATUS, &compile_status);
-    if (GL_TRUE != compile_status)
-      DLOG(ERROR) << "CopyTextureCHROMIUM: shader compilation failure.";
-#endif
-  }
-
-  // TODO(gman): Init these on demand.
-  for (int program = 0; program < kNumPrograms; ++program) {
-    const ShaderInfo& info = shader_infos[program + 1];
-    if (info.needs_egl_image_external && !have_egl_image_external) {
-      continue;
-    }
-    programs_[program] = glCreateProgram();
-    glAttachShader(programs_[program], shaders[0]);
-    glAttachShader(programs_[program], shaders[program + 1]);
-
-    glBindAttribLocation(programs_[program], kVertexPositionAttrib,
-                         "a_position");
-
-    glLinkProgram(programs_[program]);
-#ifndef NDEBUG
-    GLint linked;
-    glGetProgramiv(programs_[program], GL_LINK_STATUS, &linked);
-    if (!linked)
-      DLOG(ERROR) << "CopyTextureCHROMIUM: program link failure.";
-#endif
-
-    sampler_locations_[program] = glGetUniformLocation(programs_[program],
-                                                      "u_texSampler");
-
-    matrix_handle_[program] = glGetUniformLocation(programs_[program],
-                                                   "u_matrix");
-  }
-
-  for (int shader = 0; shader < kNumShaders; ++shader)
-    glDeleteShader(shaders[shader]);
+  vertex_shader_ = glCreateShader(GL_VERTEX_SHADER);
+  CompileShader(vertex_shader_, vertex_shader_source);
 
   decoder->RestoreBufferBindings();
 
@@ -310,9 +202,11 @@ void CopyTextureCHROMIUMResourceManager::Destroy() {
 
   glDeleteFramebuffersEXT(1, &framebuffer_);
 
-  for (int program = 0; program < kNumPrograms; ++program) {
-    if (programs_[program])
-      glDeleteProgram(programs_[program]);
+  glDeleteShader(vertex_shader_);
+  for (ProgramMap::const_iterator it = programs_.begin(); it != programs_.end();
+       ++it) {
+    const ProgramInfo& info = it->second;
+    glDeleteProgram(info.program);
   }
 
   glDeleteBuffersARB(1, &buffer_id_);
@@ -360,22 +254,45 @@ void CopyTextureCHROMIUMResourceManager::DoCopyTextureWithTransform(
     return;
   }
 
-  GLuint program = GetProgram(
-      flip_y, premultiply_alpha, unpremultiply_alpha,
-      source_target == GL_TEXTURE_EXTERNAL_OES);
-  glUseProgram(programs_[program]);
+  ShaderId shader_id =
+      GetShaderId(flip_y, premultiply_alpha, unpremultiply_alpha);
+  SamplerId sampler_id = GetSamplerId(source_target);
+
+  ProgramMapKey key(shader_id, sampler_id);
+  ProgramInfo* info = &programs_[key];
+  // Create program if necessary.
+  if (!info->program) {
+    GLuint shader = glCreateShader(GL_FRAGMENT_SHADER);
+    CompileShader(shader, fragment_shader_source[shader_id][sampler_id]);
+    info->program = glCreateProgram();
+    glAttachShader(info->program, vertex_shader_);
+    glAttachShader(info->program, shader);
+    glBindAttribLocation(info->program, kVertexPositionAttrib, "a_position");
+    glLinkProgram(info->program);
+#ifndef NDEBUG
+    GLint linked;
+    glGetProgramiv(info->program, GL_LINK_STATUS, &linked);
+    if (!linked)
+      DLOG(ERROR) << "CopyTextureCHROMIUM: program link failure.";
+#endif
+    info->sampler_locations =
+        glGetUniformLocation(info->program, "u_texSampler");
+    info->matrix_handle = glGetUniformLocation(info->program, "u_matrix");
+    glDeleteShader(shader);
+  }
+  glUseProgram(info->program);
 
 #ifndef NDEBUG
-  glValidateProgram(programs_[program]);
+  glValidateProgram(info->program);
   GLint validation_status;
-  glGetProgramiv(programs_[program], GL_VALIDATE_STATUS, &validation_status);
+  glGetProgramiv(info->program, GL_VALIDATE_STATUS, &validation_status);
   if (GL_TRUE != validation_status) {
     DLOG(ERROR) << "CopyTextureCHROMIUM: Invalid shader.";
     return;
   }
 #endif
 
-  glUniformMatrix4fv(matrix_handle_[program], 1, GL_FALSE, transform_matrix);
+  glUniformMatrix4fv(info->matrix_handle, 1, GL_FALSE, transform_matrix);
   glActiveTexture(GL_TEXTURE0);
   glBindTexture(GL_TEXTURE_2D, dest_id);
   // NVidia drivers require texture settings to be a certain way
@@ -402,7 +319,7 @@ void CopyTextureCHROMIUMResourceManager::DoCopyTextureWithTransform(
     glVertexAttribPointer(kVertexPositionAttrib, 4, GL_FLOAT, GL_FALSE,
                           4 * sizeof(GLfloat), 0);
 
-    glUniform1i(sampler_locations_[program], 0);
+    glUniform1i(info->sampler_locations, 0);
 
     glBindTexture(source_target, source_id);
     glTexParameterf(source_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);