ProvokingVertexTest.cpp

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Author : Jamie Madill
Date : 2015-10-29 10:08:09
Hash : c7a92fdb
Message : D3D11: Fix provoking vertex for flat triangle strips. Triangle strips alternate the provoking vertex based on the primitive, so use the primitive ID in the GS to determine this. This might interact poorly with primitive restart, so we might have to use a slow path for that. BUG=angleproject:754 Change-Id: I4f6f520887d4c4c52d2ad020e6db148607f68325 Reviewed-on: https://chromium-review.googlesource.com/309156 Tryjob-Request: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>
src/tests/gl_tests/ProvokingVertexTest.cpp
//
// Copyright 2015 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// ProvkingVertexTest:
//   Tests on the conformance of the provoking vertex, which applies to flat
//   shading and compatibility with D3D. See the section on 'flatshading'
//   in the ES 3 specs.
//

#include "test_utils/ANGLETest.h"

using namespace angle;

namespace
{

class ProvokingVertexTest : public ANGLETest
{
  protected:
    ProvokingVertexTest()
        : mProgram(0),
          mFramebuffer(0),
          mTexture(0),
          mTransformFeedback(0),
          mBuffer(0),
          mIntAttribLocation(-1)
    {
        setWindowWidth(64);
        setWindowHeight(64);
        setConfigRedBits(8);
        setConfigGreenBits(8);
        setConfigBlueBits(8);
        setConfigAlphaBits(8);
        setConfigDepthBits(24);
    }

    void SetUp() override
    {
        ANGLETest::SetUp();

        const std::string &vertexShader =
            "#version 300 es\n"
            "in int intAttrib;\n"
            "in vec2 position;\n"
            "flat out int attrib;\n"
            "void main() {\n"
            "  gl_Position = vec4(position, 0, 1);\n"
            "  attrib = intAttrib;\n"
            "}";

        const std::string &fragmentShader =
            "#version 300 es\n"
            "flat in int attrib;\n"
            "out int fragColor;\n"
            "void main() {\n"
            "  fragColor = attrib;\n"
            "}";

        std::vector<std::string> tfVaryings;
        tfVaryings.push_back("attrib");
        mProgram = CompileProgramWithTransformFeedback(vertexShader, fragmentShader, tfVaryings,
                                                       GL_SEPARATE_ATTRIBS);
        ASSERT_NE(0u, mProgram);

        glGenTextures(1, &mTexture);
        glBindTexture(GL_TEXTURE_2D, mTexture);
        glTexStorage2D(GL_TEXTURE_2D, 1, GL_R32I, getWindowWidth(), getWindowHeight());

        glGenFramebuffers(1, &mFramebuffer);
        glBindFramebuffer(GL_FRAMEBUFFER, mFramebuffer);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mTexture, 0);

        mIntAttribLocation = glGetAttribLocation(mProgram, "intAttrib");
        ASSERT_NE(-1, mIntAttribLocation);
        glEnableVertexAttribArray(mIntAttribLocation);

        ASSERT_GL_NO_ERROR();
    }

    void TearDown() override
    {
        if (mProgram != 0)
        {
            glDeleteProgram(mProgram);
            mProgram = 0;
        }

        if (mFramebuffer != 0)
        {
            glDeleteFramebuffers(1, &mFramebuffer);
            mFramebuffer = 0;
        }

        if (mTexture != 0)
        {
            glDeleteTextures(1, &mTexture);
            mTexture = 0;
        }

        if (mTransformFeedback != 0)
        {
            glDeleteTransformFeedbacks(1, &mTransformFeedback);
            mTransformFeedback = 0;
        }

        if (mBuffer != 0)
        {
            glDeleteBuffers(1, &mBuffer);
            mBuffer = 0;
        }

        ANGLETest::TearDown();
    }

    GLuint mProgram;
    GLuint mFramebuffer;
    GLuint mTexture;
    GLuint mTransformFeedback;
    GLuint mBuffer;
    GLint mIntAttribLocation;
};

// Test drawing a simple triangle with flat shading, and different valued vertices.
TEST_P(ProvokingVertexTest, FlatTriangle)
{
    GLint vertexData[] = {1, 2, 3, 1, 2, 3};
    glVertexAttribIPointer(mIntAttribLocation, 1, GL_INT, 0, vertexData);

    drawQuad(mProgram, "position", 0.5f);

    GLint pixelValue = 0;
    glReadPixels(0, 0, 1, 1, GL_RED_INTEGER, GL_INT, &pixelValue);

    ASSERT_GL_NO_ERROR();
    EXPECT_EQ(vertexData[2], pixelValue);
}

// Ensure that any provoking vertex shenanigans still gives correct vertex streams.
TEST_P(ProvokingVertexTest, FlatTriWithTransformFeedback)
{
    glGenTransformFeedbacks(1, &mTransformFeedback);
    glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, mTransformFeedback);

    glGenBuffers(1, &mBuffer);
    glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, mBuffer);
    glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, 128, nullptr, GL_STREAM_DRAW);

    glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, mBuffer);

    GLint vertexData[] = {1, 2, 3, 1, 2, 3};
    glVertexAttribIPointer(mIntAttribLocation, 1, GL_INT, 0, vertexData);

    glBeginTransformFeedback(GL_TRIANGLES);
    drawQuad(mProgram, "position", 0.5f);
    glEndTransformFeedback();

    GLint pixelValue = 0;
    glReadPixels(0, 0, 1, 1, GL_RED_INTEGER, GL_INT, &pixelValue);

    ASSERT_GL_NO_ERROR();
    EXPECT_EQ(vertexData[2], pixelValue);

    GLvoid *mapPointer =
        glMapBufferRange(GL_TRANSFORM_FEEDBACK_BUFFER, 0, sizeof(int) * 6, GL_MAP_READ_BIT);
    ASSERT_NE(nullptr, mapPointer);

    int *mappedInts = static_cast<int *>(mapPointer);
    for (unsigned int cnt = 0; cnt < 6; ++cnt)
    {
        EXPECT_EQ(vertexData[cnt], mappedInts[cnt]);
    }
}

// Test drawing a simple line with flat shading, and different valued vertices.
TEST_P(ProvokingVertexTest, FlatLine)
{
    GLfloat halfPixel = 1.0f / static_cast<GLfloat>(getWindowWidth());

    GLint vertexData[]     = {1, 2};
    GLfloat positionData[] = {-1.0f + halfPixel, -1.0f, -1.0f + halfPixel, 1.0f};

    glVertexAttribIPointer(mIntAttribLocation, 1, GL_INT, 0, vertexData);

    GLint positionLocation = glGetAttribLocation(mProgram, "position");
    glEnableVertexAttribArray(positionLocation);
    glVertexAttribPointer(positionLocation, 2, GL_FLOAT, GL_FALSE, 0, positionData);

    glUseProgram(mProgram);
    glDrawArrays(GL_LINES, 0, 2);

    GLint pixelValue = 0;
    glReadPixels(0, 0, 1, 1, GL_RED_INTEGER, GL_INT, &pixelValue);

    ASSERT_GL_NO_ERROR();
    EXPECT_EQ(vertexData[1], pixelValue);
}

// Test drawing a simple triangle strip with flat shading, and different valued vertices.
TEST_P(ProvokingVertexTest, FlatTriStrip)
{
    GLint vertexData[]     = {1, 2, 3, 4, 5, 6};
    GLfloat positionData[] = {-1.0f, -1.0f, -1.0f, 1.0f,  0.0f, -1.0f,
                              0.0f,  1.0f,  1.0f,  -1.0f, 1.0f, 1.0f};

    glVertexAttribIPointer(mIntAttribLocation, 1, GL_INT, 0, vertexData);

    GLint positionLocation = glGetAttribLocation(mProgram, "position");
    glEnableVertexAttribArray(positionLocation);
    glVertexAttribPointer(positionLocation, 2, GL_FLOAT, GL_FALSE, 0, positionData);

    glUseProgram(mProgram);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 6);

    std::vector<GLint> pixelBuffer(getWindowWidth() * getWindowHeight(), 0);
    glReadPixels(0, 0, getWindowWidth(), getWindowHeight(), GL_RED_INTEGER, GL_INT,
                 &pixelBuffer[0]);

    ASSERT_GL_NO_ERROR();

    for (unsigned int triIndex = 0; triIndex < 4; ++triIndex)
    {
        GLfloat sumX = positionData[triIndex * 2 + 0] + positionData[triIndex * 2 + 2] +
                       positionData[triIndex * 2 + 4];
        GLfloat sumY = positionData[triIndex * 2 + 1] + positionData[triIndex * 2 + 3] +
                       positionData[triIndex * 2 + 5];

        float centerX = sumX / 3.0f * 0.5f + 0.5f;
        float centerY = sumY / 3.0f * 0.5f + 0.5f;
        unsigned int pixelX =
            static_cast<unsigned int>(centerX * static_cast<GLfloat>(getWindowWidth()));
        unsigned int pixelY =
            static_cast<unsigned int>(centerY * static_cast<GLfloat>(getWindowHeight()));
        unsigned int pixelIndex = pixelY * getWindowWidth() + pixelX;

        unsigned int provokingVertexIndex = triIndex + 2;

        EXPECT_EQ(vertexData[provokingVertexIndex], pixelBuffer[pixelIndex]);
    }
}

// Test drawing an indexed triangle strip with flat shading and primitive restart.
TEST_P(ProvokingVertexTest, FlatTriStripPrimitiveRestart)
{
    // TODO(jmadill): Implement on the D3D back-end.
    if (isD3D11())
    {
        std::cout << "Test disabled on D3D11." << std::endl;
        return;
    }

    GLint indexData[]      = {0, 1, 2, -1, 1, 2, 3, 4, -1, 3, 4, 5};
    GLint vertexData[]     = {1, 2, 3, 4, 5, 6};
    GLfloat positionData[] = {-1.0f, -1.0f, -1.0f, 1.0f,  0.0f, -1.0f,
                              0.0f,  1.0f,  1.0f,  -1.0f, 1.0f, 1.0f};

    glVertexAttribIPointer(mIntAttribLocation, 1, GL_INT, 0, vertexData);

    GLint positionLocation = glGetAttribLocation(mProgram, "position");
    glEnableVertexAttribArray(positionLocation);
    glVertexAttribPointer(positionLocation, 2, GL_FLOAT, GL_FALSE, 0, positionData);

    glDisable(GL_CULL_FACE);
    glEnable(GL_PRIMITIVE_RESTART_FIXED_INDEX);
    glUseProgram(mProgram);
    glDrawElements(GL_TRIANGLE_STRIP, 12, GL_UNSIGNED_INT, indexData);

    std::vector<GLint> pixelBuffer(getWindowWidth() * getWindowHeight(), 0);
    glReadPixels(0, 0, getWindowWidth(), getWindowHeight(), GL_RED_INTEGER, GL_INT,
                 &pixelBuffer[0]);

    ASSERT_GL_NO_ERROR();

    // Account for primitive restart when checking the tris.
    GLint triOffsets[] = {0, 4, 5, 9};

    for (unsigned int triIndex = 0; triIndex < 4; ++triIndex)
    {
        GLint vertexA = indexData[triOffsets[triIndex] + 0];
        GLint vertexB = indexData[triOffsets[triIndex] + 1];
        GLint vertexC = indexData[triOffsets[triIndex] + 2];

        GLfloat sumX =
            positionData[vertexA * 2] + positionData[vertexB * 2] + positionData[vertexC * 2];
        GLfloat sumY = positionData[vertexA * 2 + 1] + positionData[vertexB * 2 + 1] +
                       positionData[vertexC * 2 + 1];

        float centerX = sumX / 3.0f * 0.5f + 0.5f;
        float centerY = sumY / 3.0f * 0.5f + 0.5f;
        unsigned int pixelX =
            static_cast<unsigned int>(centerX * static_cast<GLfloat>(getWindowWidth()));
        unsigned int pixelY =
            static_cast<unsigned int>(centerY * static_cast<GLfloat>(getWindowHeight()));
        unsigned int pixelIndex = pixelY * getWindowWidth() + pixelX;

        unsigned int provokingVertexIndex = triIndex + 2;

        EXPECT_EQ(vertexData[provokingVertexIndex], pixelBuffer[pixelIndex]);
    }
}

ANGLE_INSTANTIATE_TEST(ProvokingVertexTest, ES3_D3D11(), ES3_OPENGL());

}  // anonymous namespace
kc3-lang/angle/src/tests/gl_tests/ProvokingVertexTest.cpp

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kc3-lang/angle /src/tests/gl_tests/ProvokingVertexTest.cpp
