Purpose of the Sample:
Demonstrates how to texture map a quad. This sample is based on the learnopengl.com tutorial.
CGame.h
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#ifndef __CGAME__ #define __CGAME__ #include <glad/glad.h> #include "shader_s.h" class CGame { public: CGame() {}; void Initialize(); void Shutdown(); void Render(); void OnResize(int width, int height); private: void SetupVAO(); void SetupGPUProgram(); void SetupTexture(); unsigned int m_VAO; unsigned int m_Texture; Shader* m_pShader; }; #endif |
CGame.cpp
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#include "CGame.h" #define STB_IMAGE_IMPLEMENTATION #include "stb_image/stb_image.h" void CGame::Initialize() { SetupGPUProgram(); SetupTexture(); SetupVAO(); } void CGame::Shutdown() { } void CGame::OnResize(int width, int height) { glViewport(0, 0, width, height); } void CGame::Render() { glClearColor(0.2f, 0.3f, 0.3f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); glBindTexture(GL_TEXTURE_2D, m_Texture); m_pShader->use(); glBindVertexArray(m_VAO); glDrawArrays(GL_TRIANGLES, 0, 6); } void CGame::SetupVAO() { float vertices[] = { 1.0f, -1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, -1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, -1.0f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, -1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, -1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, }; unsigned int vbo; glGenBuffers(1, &vbo); glGenVertexArrays(1, &m_VAO); // ..:: Initialization code (done once (unless your object frequently changes)) :: .. // 1. bind Vertex Array Object glBindVertexArray(m_VAO); // 2. copy our vertices array in a buffer for OpenGL to use glBindBuffer(GL_ARRAY_BUFFER, vbo); glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); // 3. then set our vertex attributes pointers // Position Attribute. glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0); glEnableVertexAttribArray(0); // Color Attribute. glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float))); glEnableVertexAttribArray(1); // UV Attribute. glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float))); glEnableVertexAttribArray(2); } void CGame::SetupGPUProgram() { m_pShader = new Shader("vertex.glsl", "fragment.glsl"); } void CGame::SetupTexture() { int width, height, nrChannels; unsigned char *data = stbi_load("awesomeface.jpg", &width, &height, &nrChannels, 0); glGenTextures(1, &m_Texture); glBindTexture(GL_TEXTURE_2D, m_Texture); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data); glGenerateMipmap(GL_TEXTURE_2D); } |
vertex.glsl
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#version 330 core layout (location = 0) in vec3 aPos; layout(location = 1) in vec3 aColor; layout(location = 2) in vec2 aUV; out vec3 vertexColor; out vec2 vertexUV; void main() { vertexColor = aColor; vertexUV = aUV; gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0); } |
fragment.glsl
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#version 330 core out vec4 FragColor; in vec3 vertexColor; in vec2 vertexUV; uniform sampler2D myTexture; void main() { vec2 ndc = vertexUV * 2.0 - 1.0; //vec3 color = vertexColor * length(ndc); vec3 color = texture(myTexture, vertexUV).rgb; FragColor = vec4(color.rgb, 1.0f); } |