feat: adapt colorspace for Android

Author: ZGaopeng

android/src/main/cpp/iris_rtc_rendering_android.cc

@@ -12,6 +12,7 @@
 #include <jni.h>
 #include <memory>
 #include <vector>
+#include <cstring>
 
 namespace agora {
 namespace iris {
@@ -508,6 +509,11 @@ class YUVRendering final : public RenderingOp {
     uTextureLoc_ = glGetUniformLocation(program, "uTexture");
     vTextureLoc_ = glGetUniformLocation(program, "vTexture");
 
+    // Get locations for ColorSpace uniforms
+    colorMatrixLoc_ = glGetUniformLocation(program, "uColorMatrix");
+    rangeLoc_ = glGetUniformLocation(program, "uRange");
+    transferLoc_ = glGetUniformLocation(program, "uTransfer");
+
     glGenTextures(3, texs_);
     CHECK_GL_ERROR()
   }
@@ -618,6 +624,52 @@ class YUVRendering final : public RenderingOp {
                  GL_LUMINANCE, GL_UNSIGNED_BYTE, vBuffer);
     CHECK_GL_ERROR()
 
+    // Update color space uniforms if available
+    if (colorMatrixLoc_ != -1) {
+      float bt709[9] = {
+          1.0f, 1.0f, 1.0f,
+          0.0f, -0.39465f, 2.03211f,
+          1.13983f, -0.58060f, 0.0f
+      };
+      float bt2020[9] = {
+          1.0f, 1.0f, 1.0f,
+          0.0f, -0.16455f, 1.88140f,
+          1.47460f, -0.57135f, 0.0f
+      };
+      float smpte170m[9] = {
+          1.0f, 1.0f, 1.0f,
+          0.0f, -0.39173f, 2.01700f,
+          1.59580f, -0.81290f, 0.0f
+      };
+
+      float mat[9];
+      int matrixId = (int)video_frame->colorSpace.matrix;
+      switch (matrixId) {
+        case agora::media::base::ColorSpace::MATRIXID_BT2020_NCL:
+          memcpy(mat, bt2020, sizeof(mat));
+          break;
+        case agora::media::base::ColorSpace::MATRIXID_SMPTE170M:
+          memcpy(mat, smpte170m, sizeof(mat));
+          break;
+        case agora::media::base::ColorSpace::MATRIXID_BT709:
+        default:
+          memcpy(mat, bt709, sizeof(mat));
+          break;
+      }
+      glUniformMatrix3fv(colorMatrixLoc_, 1, GL_FALSE, mat);
+    }
+
+    // 2. Set Range
+    if (rangeLoc_ != -1) {
+      int rangeVal = (video_frame->colorSpace.range == agora::media::base::ColorSpace::RANGEID_LIMITED) ? 1 : 0;
+      glUniform1i(rangeLoc_, rangeVal);
+    }
+
+    // 3. Set Transfer Function
+    if (transferLoc_ != -1) {
+      glUniform1i(transferLoc_, (int)video_frame->colorSpace.transfer);
+    }
+
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     CHECK_GL_ERROR()
 
@@ -642,8 +694,8 @@ class YUVRendering final : public RenderingOp {
       "attribute vec2 aTextCoord;\n"
       "varying vec2 vTextCoord;\n"
       "void main() {\n"
-      "    vTextCoord = vec2(aTextCoord.x, 1.0 - aTextCoord.y);\n"
-      "    gl_Position = aPosition;\n"
+      "  gl_Position = aPosition;\n"
+      "  vTextCoord = aTextCoord;\n"
       "}\n";
 
   const char *frag_shader_yuv_ =
@@ -652,15 +704,38 @@ class YUVRendering final : public RenderingOp {
       "uniform sampler2D yTexture;\n"
       "uniform sampler2D uTexture;\n"
       "uniform sampler2D vTexture;\n"
+      "uniform mat3 uColorMatrix;\n"
+      "uniform int uRange;\n"
+      "uniform int uTransfer;\n"
+      "\n"
+      "vec3 applyTransfer(vec3 c, int transferId) {\n"
+      "  if (transferId == 8) { return c; }\n" // LINEAR
+      "  else if (transferId == 4) { return pow(c, vec3(1.0/2.2)); }\n" // GAMMA22
+      "  else if (transferId == 5) { return pow(c, vec3(1.0/2.8)); }\n" // GAMMA28
+      "  else if (transferId == 1) { return pow(c, vec3(1.0/2.4)); }\n" // BT709 approx
+      "  return c;\n"
+      "}\n"
+      "\n"
       "void main() {\n"
-      "    vec3 yuv;\n"
-      "    vec3 rgb;\n"
-      "    yuv.r = texture2D(yTexture, vTextCoord).r;\n"
-      "    yuv.g = texture2D(uTexture, vTextCoord).r - 0.5;\n"
-      "    yuv.b = texture2D(vTexture, vTextCoord).r - 0.5;\n"
-      "    rgb = mat3(1.0, 1.0, 1.0, 0.0, -0.39465, 2.03211, 1.13983, "
-      "-0.58060, 0.0) * yuv;\n"
-      "    gl_FragColor = vec4(rgb, 1.0);\n"
+      "  float y = texture2D(yTexture, vTextCoord).r;\n"
+      "  float u = texture2D(uTexture, vTextCoord).r - 0.5;\n"
+      "  float v = texture2D(vTexture, vTextCoord).r - 0.5;\n"
+      "\n"
+      "  // 1. Range Conversion\n"
+      "  if (uRange == 1) { // Limited Range to Full Range\n"
+      "    y = (y - 16.0/255.0) * (255.0/219.0);\n"
+      "    u = u * (224.0/255.0);\n"
+      "    v = v * (224.0/255.0);\n"
+      "  }\n"
+      "\n"
+      "  // 2. YUV to RGB Conversion with dynamic matrix\n"
+      "  vec3 yuv = vec3(y, u, v);\n"
+      "  vec3 rgb = uColorMatrix * yuv;\n"
+      "\n"
+      "  // 3. Apply Transfer Function (Gamma Correction)\n"
+      "  rgb = applyTransfer(rgb, uTransfer);\n"
+      "\n"
+      "  gl_FragColor = vec4(clamp(rgb, 0.0, 1.0), 1.0);\n"
       "}\n";
 
   // clang-format off
@@ -680,6 +755,9 @@ class YUVRendering final : public RenderingOp {
   GLint yTextureLoc_;
   GLint uTextureLoc_;
   GLint vTextureLoc_;
+  GLint colorMatrixLoc_ = -1;
+  GLint rangeLoc_ = -1;
+  GLint transferLoc_ = -1;
 
   std::unique_ptr<ScopedShader> shader_;
 };