example_triangle.cpp

#include "common.h"
#include "example_triangle.h"


constexpr const char* s_vertexShader = R"(
#version 400 core

layout(location = 0) in vec4 aColor;
layout(location = 1) in vec4 aPosition;

out vec4 vColor;

void main()
{
    gl_Position = vec4(aPosition);
    vColor = aColor;
}
)";

constexpr const char* s_fragmentShader = R"(
#version 400 core

in vec4 vColor;
out vec4 FragColor;

void main()
{
    FragColor = vColor;
}
)";


ExampleTriangle::ExampleTriangle() {
    // create shader group
    std::string errorLog(1024, '\0');
    GX2VertexShader* vertexShader = GLSL_CompileVertexShader(s_vertexShader, errorLog.data(), (int)errorLog.size(), GLSL_COMPILER_FLAG_NONE);
    if (!vertexShader) {
        WHBLogPrintf("Vertex shader compilation failed for triangle example: %s", errorLog.data());
        return;
    }
    GX2PixelShader* pixelShader = GLSL_CompilePixelShader(s_fragmentShader, errorLog.data(), (int)errorLog.size(), GLSL_COMPILER_FLAG_NONE);
    if (!pixelShader) {
        WHBLogPrintf("Pixel shader compilation failed for triangle example: %s", errorLog.data());
        return;
    }
    memset(&s_shaderGroup, 0, sizeof(WHBGfxShaderGroup));
    s_shaderGroup.vertexShader = vertexShader;
    s_shaderGroup.pixelShader = pixelShader;
    GX2Invalidate(GX2_INVALIDATE_MODE_CPU_SHADER, s_shaderGroup.vertexShader->program, s_shaderGroup.vertexShader->size);
    GX2Invalidate(GX2_INVALIDATE_MODE_CPU_SHADER, s_shaderGroup.pixelShader->program, s_shaderGroup.pixelShader->size);

    WHBGfxInitShaderAttribute(&s_shaderGroup, "aPosition", 0, 0, GX2_ATTRIB_FORMAT_FLOAT_32_32_32_32);
    WHBGfxInitShaderAttribute(&s_shaderGroup, "aColor", 1, 0, GX2_ATTRIB_FORMAT_FLOAT_32_32_32_32);
    WHBGfxInitFetchShader(&s_shaderGroup);

    // upload vertex position
    s_positionBuffer.flags = GX2R_RESOURCE_BIND_VERTEX_BUFFER | GX2R_RESOURCE_USAGE_CPU_READ | GX2R_RESOURCE_USAGE_CPU_WRITE | GX2R_RESOURCE_USAGE_GPU_READ;
    s_positionBuffer.elemSize = 4 * 4;
    s_positionBuffer.elemCount = 3;
    GX2RCreateBuffer(&s_positionBuffer);
    void *posUploadBuffer = GX2RLockBufferEx(&s_positionBuffer, GX2R_RESOURCE_BIND_NONE);
    memcpy(posUploadBuffer, s_positionData, s_positionBuffer.elemSize * s_positionBuffer.elemCount);
    GX2RUnlockBufferEx(&s_positionBuffer, GX2R_RESOURCE_BIND_NONE);

    // upload vertex color
    s_colorBuffer.flags = GX2R_RESOURCE_BIND_VERTEX_BUFFER | GX2R_RESOURCE_USAGE_CPU_READ | GX2R_RESOURCE_USAGE_CPU_WRITE | GX2R_RESOURCE_USAGE_GPU_READ;
    s_colorBuffer.elemSize = 4 * 4;
    s_colorBuffer.elemCount = 3;
    GX2RCreateBuffer(&s_colorBuffer);
    void* colUploadBuffer = GX2RLockBufferEx(&s_colorBuffer, GX2R_RESOURCE_BIND_NONE);
    memcpy(colUploadBuffer, s_colorData, s_colorBuffer.elemSize * s_colorBuffer.elemCount);
    GX2RUnlockBufferEx(&s_colorBuffer, GX2R_RESOURCE_BIND_NONE);
}

void ExampleTriangle::Draw() {
    // animate triangle colors
    float *colors = (float *)GX2RLockBufferEx(&s_colorBuffer, GX2R_RESOURCE_BIND_NONE);
    colors[0] = 1.0f;
    colors[1] = colors[1] >= 1.0f ? 0.0f : (colors[1] + 0.01f);
    colors[2] = colors[2] >= 1.0f ? 0.0f : (colors[2] + 0.01f);
    colors[3] = 1.0f;

    colors[4] = colors[4] >= 1.0f ? 0.0f : (colors[4] + 0.01f);
    colors[5] = 1.0f;
    colors[6] = colors[6] >= 1.0f ? 0.0f : (colors[6] + 0.01f);
    colors[7] = 1.0f;

    colors[8] = colors[8] >= 1.0f ? 0.0f : (colors[8] + 0.01f);
    colors[9] = colors[9] >= 1.0f ? 0.0f : (colors[9] + 0.01f);
    colors[10] = 1.0f;
    colors[11] = 1.0f;
    GX2RUnlockBufferEx(&s_colorBuffer, GX2R_RESOURCE_BIND_NONE);

    // render triangle
    WHBGfxBeginRender();

    WHBGfxBeginRenderTV();
    WHBGfxClearColor(0.0f, 0.0f, 1.0f, 1.0f);
    GX2SetFetchShader(&s_shaderGroup.fetchShader);
    GX2SetVertexShader(s_shaderGroup.vertexShader);
    GX2SetPixelShader(s_shaderGroup.pixelShader);
    GX2RSetAttributeBuffer(&s_positionBuffer, 0, s_positionBuffer.elemSize, 0);
    GX2RSetAttributeBuffer(&s_colorBuffer, 1, s_colorBuffer.elemSize, 0);
    GX2DrawEx(GX2_PRIMITIVE_MODE_TRIANGLES, 3, 0, 1);
    WHBGfxFinishRenderTV();

    WHBGfxBeginRenderDRC();
    WHBGfxClearColor(1.0f, 0.0f, 1.0f, 1.0f);
    GX2SetFetchShader(&s_shaderGroup.fetchShader);
    GX2SetVertexShader(s_shaderGroup.vertexShader);
    GX2SetPixelShader(s_shaderGroup.pixelShader);
    GX2RSetAttributeBuffer(&s_positionBuffer, 0, s_positionBuffer.elemSize, 0);
    GX2RSetAttributeBuffer(&s_colorBuffer, 1, s_colorBuffer.elemSize, 0);
    GX2DrawEx(GX2_PRIMITIVE_MODE_TRIANGLES, 3, 0, 1);
    WHBGfxFinishRenderDRC();

    WHBGfxFinishRender();
}

ExampleTriangle::~ExampleTriangle() {
    GX2RDestroyBufferEx(&s_positionBuffer, GX2R_RESOURCE_BIND_NONE);
    GX2RDestroyBufferEx(&s_colorBuffer, GX2R_RESOURCE_BIND_NONE);
}