kc3-lang/angle/tests/angle_tests/TransformFeedbackTest.cpp

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• Hash : 02f18b88
  Author :
  Date : 2014-09-17T11:42:17
  

  Don't skip draw calls on zero-sized viewports.
  
  If transform feedback is active, primitives still need to be rendered even
  if no pixels are written to the framebuffer.
  
  Instead of checking for active transform feedback, simply remove the draw
  call skipping optimization since it is most likely an application mistake to
  draw with a zero sized viewport and we shouldn't optimize for this case.
  
  This change doesn't affect the clear calls because the viewport is set to the
  framebuffer size which is non-zero.
  
  BUG=angle:743
  
  Change-Id: I04af9d6de5aad3040e3c6b3c24990e107e21ad36
  Reviewed-on: https://chromium-review.googlesource.com/218508
  Reviewed-by: Brandon Jones <bajones@chromium.org>
  Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
  Tested-by: Geoff Lang <geofflang@chromium.org>
  

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• tests/angle_tests/TransformFeedbackTest.cpp

• #include "ANGLETest.h"
  
  class TransformFeedbackTest : public ANGLETest
  {
    protected:
        TransformFeedbackTest()
      {
          setWindowWidth(128);
          setWindowHeight(128);
          setConfigRedBits(8);
          setConfigGreenBits(8);
          setConfigBlueBits(8);
          setConfigAlphaBits(8);
          setClientVersion(3);
      }
  
      virtual void SetUp()
      {
          ANGLETest::SetUp();
  
          const std::string vertexShaderSource = SHADER_SOURCE
          (
              precision highp float;
              attribute vec4 position;
  
              void main()
              {
                  gl_Position = position;
              }
          );
  
          const std::string fragmentShaderSource = SHADER_SOURCE
          (
              precision highp float;
  
              void main()
              {
                  gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
              }
          );
  
          mProgram = CompileProgram(vertexShaderSource, fragmentShaderSource);
          if (mProgram == 0)
          {
              FAIL() << "shader compilation failed.";
          }
  
          glGenBuffers(1, &mTransformFeedbackBuffer);
          mTransformFeedbackBufferSize = 1 << 24; // ~16MB
          glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, mTransformFeedbackBuffer);
          glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, mTransformFeedbackBufferSize, NULL, GL_STATIC_DRAW);
  
          ASSERT_GL_NO_ERROR();
      }
  
      virtual void TearDown()
      {
          glDeleteProgram(mProgram);
          glDeleteBuffers(1, &mTransformFeedbackBuffer);
          ANGLETest::TearDown();
      }
  
      GLuint mProgram;
  
      size_t mTransformFeedbackBufferSize;
      GLuint mTransformFeedbackBuffer;
  };
  
  TEST_F(TransformFeedbackTest, ZeroSizedViewport)
  {
      // Set the program's transform feedback varyings (just gl_Position)
      const GLchar* transformFeedbackVaryings[] =
      {
          "gl_Position"
      };
      glTransformFeedbackVaryings(mProgram, ArraySize(transformFeedbackVaryings), transformFeedbackVaryings, GL_INTERLEAVED_ATTRIBS);
      glLinkProgram(mProgram);
  
      // Re-link the program
      GLint linkStatus;
      glGetProgramiv(mProgram, GL_LINK_STATUS, &linkStatus);
      ASSERT_NE(linkStatus, 0);
  
      glUseProgram(mProgram);
  
      // Bind the buffer for transform feedback output and start transform feedback
      glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, mTransformFeedbackBuffer);
      glBeginTransformFeedback(GL_TRIANGLES);
  
      // Create a query to check how many primitives were written
      GLuint primitivesWrittenQuery = 0;
      glGenQueries(1, &primitivesWrittenQuery);
      glBeginQuery(GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, primitivesWrittenQuery);
  
      // Set a viewport that would result in no pixels being written to the framebuffer and draw
      // a quad
      glViewport(0, 0, 0, 0);
  
      drawQuad(mProgram, "position", 0.5f);
  
      // End the query and transform feedkback
      glEndQuery(GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN);
      glEndTransformFeedback();
  
      // Check how many primitives were written and verify that some were written even if
      // no pixels were rendered
      GLuint primitivesWritten = 0;
      glGetQueryObjectuiv(primitivesWrittenQuery, GL_QUERY_RESULT_EXT, &primitivesWritten);
      EXPECT_GL_NO_ERROR();
  
      EXPECT_EQ(primitivesWritten, 2);
  }
  

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