//
// 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.
//
// DrawElementsTest:
//   Tests for indexed draws.
//

#include "test_utils/ANGLETest.h"
#include "test_utils/gl_raii.h"

using namespace angle;

namespace
{

class DrawElementsTest : public ANGLETest
{
  protected:
    DrawElementsTest() : mProgram(0u)
    {
        setWindowWidth(64);
        setWindowHeight(64);
        setConfigRedBits(8);
        setConfigGreenBits(8);
    }

    ~DrawElementsTest()
    {
        for (GLuint indexBuffer : mIndexBuffers)
        {
            if (indexBuffer != 0)
            {
                glDeleteBuffers(1, &indexBuffer);
            }
        }

        for (GLuint vertexArray : mVertexArrays)
        {
            if (vertexArray != 0)
            {
                glDeleteVertexArrays(1, &vertexArray);
            }
        }

        for (GLuint vertexBuffer : mVertexBuffers)
        {
            if (vertexBuffer != 0)
            {
                glDeleteBuffers(1, &vertexBuffer);
            }
        }

        if (mProgram != 0u)
        {
            glDeleteProgram(mProgram);
        }
    }

    std::vector<GLuint> mIndexBuffers;
    std::vector<GLuint> mVertexArrays;
    std::vector<GLuint> mVertexBuffers;
    GLuint mProgram;
};

// Test no error is generated when using client-side arrays, indices = nullptr and count = 0
TEST_P(DrawElementsTest, ClientSideNullptrArrayZeroCount)
{
    const std::string &vert =
        "attribute vec3 a_pos;\n"
        "void main()\n"
        "{\n"
        "    gl_Position = vec4(a_pos, 1.0);\n"
        "}\n";

    ANGLE_GL_PROGRAM(program, vert, essl1_shaders::fs::Blue());

    GLint posLocation = glGetAttribLocation(program.get(), "a_pos");
    ASSERT_NE(-1, posLocation);
    glUseProgram(program.get());

    const auto &vertices = GetQuadVertices();

    GLBuffer vertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer.get());
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices.size(), vertices.data(),
                 GL_STATIC_DRAW);

    glVertexAttribPointer(posLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(posLocation);
    ASSERT_GL_NO_ERROR();

    // "If drawElements is called with a count greater than zero, and no WebGLBuffer is bound to the
    // ELEMENT_ARRAY_BUFFER binding point, an INVALID_OPERATION error is generated."
    glDrawElements(GL_TRIANGLES, 1, GL_UNSIGNED_BYTE, nullptr);
    EXPECT_GL_ERROR(GL_INVALID_OPERATION);

    // count == 0 so it's fine to have no element array buffer bound.
    glDrawElements(GL_TRIANGLES, 0, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();
}

// Test a state desync that can occur when using a streaming index buffer in GL in concert with
// deleting the applied index buffer.
TEST_P(DrawElementsTest, DeletingAfterStreamingIndexes)
{
    // Init program
    const std::string &vertexShader =
        "attribute vec2 position;\n"
        "attribute vec2 testFlag;\n"
        "varying vec2 v_data;\n"
        "void main() {\n"
        "  gl_Position = vec4(position, 0, 1);\n"
        "  v_data = testFlag;\n"
        "}";

    const std::string &fragmentShader =
        "varying highp vec2 v_data;\n"
        "void main() {\n"
        "  gl_FragColor = vec4(v_data, 0, 1);\n"
        "}";

    mProgram = CompileProgram(vertexShader, fragmentShader);
    ASSERT_NE(0u, mProgram);
    glUseProgram(mProgram);

    GLint positionLocation = glGetAttribLocation(mProgram, "position");
    ASSERT_NE(-1, positionLocation);

    GLint testFlagLocation = glGetAttribLocation(mProgram, "testFlag");
    ASSERT_NE(-1, testFlagLocation);

    mIndexBuffers.resize(3u);
    glGenBuffers(3, &mIndexBuffers[0]);

    mVertexArrays.resize(2);
    glGenVertexArrays(2, &mVertexArrays[0]);

    mVertexBuffers.resize(2);
    glGenBuffers(2, &mVertexBuffers[0]);

    std::vector<GLuint> indexData[2];
    indexData[0].push_back(0);
    indexData[0].push_back(1);
    indexData[0].push_back(2);
    indexData[0].push_back(2);
    indexData[0].push_back(3);
    indexData[0].push_back(0);

    indexData[1] = indexData[0];
    for (GLuint &item : indexData[1])
    {
        item += 4u;
    }

    std::vector<GLfloat> positionData;
    // quad verts
    positionData.push_back(-1.0f);
    positionData.push_back(1.0f);
    positionData.push_back(-1.0f);
    positionData.push_back(-1.0f);
    positionData.push_back(1.0f);
    positionData.push_back(-1.0f);
    positionData.push_back(1.0f);
    positionData.push_back(1.0f);

    // Repeat position data
    positionData.push_back(-1.0f);
    positionData.push_back(1.0f);
    positionData.push_back(-1.0f);
    positionData.push_back(-1.0f);
    positionData.push_back(1.0f);
    positionData.push_back(-1.0f);
    positionData.push_back(1.0f);
    positionData.push_back(1.0f);

    std::vector<GLfloat> testFlagData;
    // red
    testFlagData.push_back(1.0f);
    testFlagData.push_back(0.0f);
    testFlagData.push_back(1.0f);
    testFlagData.push_back(0.0f);
    testFlagData.push_back(1.0f);
    testFlagData.push_back(0.0f);
    testFlagData.push_back(1.0f);
    testFlagData.push_back(0.0f);

    // green
    testFlagData.push_back(0.0f);
    testFlagData.push_back(1.0f);
    testFlagData.push_back(0.0f);
    testFlagData.push_back(1.0f);
    testFlagData.push_back(0.0f);
    testFlagData.push_back(1.0f);
    testFlagData.push_back(0.0f);
    testFlagData.push_back(1.0f);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBuffers[0]);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLuint) * indexData[0].size(), &indexData[0][0],
                 GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBuffers[2]);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLuint) * indexData[0].size(), &indexData[0][0],
                 GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBuffers[1]);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLuint) * indexData[1].size(), &indexData[1][0],
                 GL_STATIC_DRAW);

    // Initialize first vertex array with second index buffer
    glBindVertexArray(mVertexArrays[0]);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBuffers[1]);
    glBindBuffer(GL_ARRAY_BUFFER, mVertexBuffers[0]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * positionData.size(), &positionData[0],
                 GL_STATIC_DRAW);
    glVertexAttribPointer(positionLocation, 2, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 2, nullptr);
    glEnableVertexAttribArray(positionLocation);

    glBindBuffer(GL_ARRAY_BUFFER, mVertexBuffers[1]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * testFlagData.size(), &testFlagData[0],
                 GL_STATIC_DRAW);
    glVertexAttribPointer(testFlagLocation, 2, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 2, nullptr);
    glEnableVertexAttribArray(testFlagLocation);

    // Initialize second vertex array with first index buffer
    glBindVertexArray(mVertexArrays[1]);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBuffers[0]);

    glBindBuffer(GL_ARRAY_BUFFER, mVertexBuffers[0]);
    glVertexAttribPointer(positionLocation, 2, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 2, nullptr);
    glEnableVertexAttribArray(positionLocation);

    glBindBuffer(GL_ARRAY_BUFFER, mVertexBuffers[1]);
    glVertexAttribPointer(testFlagLocation, 2, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 2, nullptr);
    glEnableVertexAttribArray(testFlagLocation);

    ASSERT_GL_NO_ERROR();

    glBindVertexArray(mVertexArrays[0]);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
    EXPECT_PIXEL_EQ(0, 0, 0, 255, 0, 255);

    glBindVertexArray(mVertexArrays[1]);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
    EXPECT_PIXEL_EQ(0, 0, 255, 0, 0, 255);

    glBindVertexArray(mVertexArrays[0]);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
    EXPECT_PIXEL_EQ(0, 0, 0, 255, 0, 255);

    // Trigger the bug here.
    glDeleteBuffers(1, &mIndexBuffers[2]);

    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
    EXPECT_PIXEL_EQ(0, 0, 0, 255, 0, 255);

    ASSERT_GL_NO_ERROR();
}
// Test that the offset in the index buffer is forced to be a multiple of the element size
TEST_P(DrawElementsTest, DrawElementsTypeAlignment)
{
    const std::string &vert =
        "attribute vec3 a_pos;\n"
        "void main()\n"
        "{\n"
        "    gl_Position = vec4(a_pos, 1.0);\n"
        "}\n";

    ANGLE_GL_PROGRAM(program, vert, essl1_shaders::fs::Blue());

    GLint posLocation = glGetAttribLocation(program, "a_pos");
    ASSERT_NE(-1, posLocation);
    glUseProgram(program);

    const auto &vertices = GetQuadVertices();

    GLBuffer vertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices.size(), vertices.data(),
                 GL_STATIC_DRAW);

    glVertexAttribPointer(posLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(posLocation);

    GLBuffer indexBuffer;
    const GLubyte indices1[] = {0, 0, 0, 0, 0, 0};
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices1), indices1, GL_STATIC_DRAW);

    ASSERT_GL_NO_ERROR();

    const char *zeroIndices = nullptr;

    glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_SHORT, zeroIndices);
    ASSERT_GL_NO_ERROR();

    const GLubyte indices2[] = {0, 0, 0, 0, 0};
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices2), indices2, GL_STATIC_DRAW);

    glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_SHORT, zeroIndices + 1);
    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
}

ANGLE_INSTANTIATE_TEST(DrawElementsTest, ES3_OPENGL(), ES3_OPENGLES());
}
