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PiperOrigin-RevId: 253489161

mediapipe/gpu/gl_simple_shaders.h

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+// Copyright 2019 The MediaPipe Authors.
+//
+// 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.
+
+#ifndef MEDIAPIPE_GPU_GL_SIMPLE_SHADERS_H_
+#define MEDIAPIPE_GPU_GL_SIMPLE_SHADERS_H_
+
+#include "mediapipe/gpu/gl_base.h"
+
+namespace mediapipe {
+
+// Leaves vertex and texture coordinates as they are.
+// Input attributes:
+//   vec4 position - vertex position in clip space (-1..1)
+//   vec4 texture_coordinate - texture coordinate for each vertex in
+//                             normalized texture space (0..1)
+// Output varying:
+//   vec2 sample_coordinate - texture coordinate for shader
+extern const GLchar* const kBasicVertexShader;
+
+// Leaves vertex and texture coordinates as they are.
+// Input attributes:
+//   vec4 position - vertex position
+//   vec4 texture_coordinate - texture coordinate
+// Input uniform:
+//   vec4 scale - scale factor for vertices
+// Output varying:
+//   vec2 sample_coordinate - texture coordinate for shader
+extern const GLchar* const kScaledVertexShader;
+
+// Outputs the texture as it is.
+// Input varying:
+//   vec2 sample_coordinate - texture coordinate
+// Input uniform:
+//   sampler2d video_frame - texture
+extern const GLchar* const kBasicTexturedFragmentShader;
+
+// Same as kBasicTexturedFragmentShader
+// except using OES textures.
+extern const GLchar* const kBasicTexturedFragmentShaderOES;
+
+// Paints the fragment with a flat color.
+// Input uniform:
+//   vec3 color - the RGB color.
+extern const GLchar* const kFlatColorFragmentShader;
+
+// Multiplies each R, G, B value for a weight.
+// Input varying:
+//   vec2 sample_coordinate - texture coordinate
+// Input uniform:
+//   sampler2d video_frame - texture
+//   vec3 weights - r,g,b weights
+extern const GLchar* const kRgbWeightFragmentShader;
+
+// Converts a YUV input into RGB.
+// Input uniform:
+//   sampler2D video_frame_y - Y texture
+//   sampler2D video_frame_uv - UV texture
+extern const GLchar* const kYUV2TexToRGBFragmentShader;
+
+// A square covering the full clip space.
+static const GLfloat kBasicSquareVertices[] = {
+    -1.0f, -1.0f,  // bottom left
+    1.0f,  -1.0f,  // bottom right
+    -1.0f, 1.0f,   // top left
+    1.0f,  1.0f,   // top right
+};
+
+// Temporary macros to copy vertices.
+#define V(source, n) source[2 * (n)], source[2 * (n) + 1]
+#define V4(source, a, b, c, d) \
+  V(source, a), V(source, b), V(source, c), V(source, d)
+
+// A square covering the full clip space, rotated 90 degrees counterclockwise.
+static const GLfloat kBasicSquareVertices90[] = {
+    V4(kBasicSquareVertices, 2, 0, 3, 1)};
+
+// A square covering the full clip space, rotated 180 degrees counterclockwise.
+static const GLfloat kBasicSquareVertices180[] = {
+    V4(kBasicSquareVertices, 3, 2, 1, 0)};
+
+// A square covering the full clip space, rotated 270 degrees counterclockwise.
+static const GLfloat kBasicSquareVertices270[] = {
+    V4(kBasicSquareVertices, 1, 3, 0, 2)};
+
+// Places a texture on kBasicSquareVertices with normal alignment.
+static const GLfloat kBasicTextureVertices[] = {
+    0.0f, 0.0f,  // bottom left
+    1.0f, 0.0f,  // bottom right
+    0.0f, 1.0f,  // top left
+    1.0f, 1.0f,  // top right
+};
+
+// Places a texture on kBasicSquareVertices, flipped vertically.
+static const GLfloat kBasicTextureVerticesFlipY[] = {
+    V4(kBasicTextureVertices, 2, 3, 0, 1)};
+
+#undef V4
+#undef V
+
+// Used in shaders to differentiate desktop OpenGL vs OpenGL ES.
+// The newer spec requires this to be the first line of a shader.
+// Desktop OpenGL 3.3+ = #version 330
+#ifndef GL_ES_VERSION_2_0
+#define GLES_VERSION_COMPAT "#version 330 \n"
+#else
+#define GLES_VERSION_COMPAT "\n"
+#endif  // GL_ES_VERSION_2_0
+
+// Used in vertex shaders to differentiate different versions of OpenGL.
+extern const GLchar* const kMediaPipeVertexShaderPreamble;
+
+// Used in fragment shaders to differentiate different versions of OpenGL.
+extern const GLchar* const kMediaPipeFragmentShaderPreamble;
+
+}  // namespace mediapipe
+
+#endif  // MEDIAPIPE_GPU_GL_SIMPLE_SHADERS_H_