118 lines
5.3 KiB
C++
118 lines
5.3 KiB
C++
#pragma once
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// Must be the first include
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#include <glad/glad.h>
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// Other includes
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#include "Shader.h"
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#include "Spatial.h"
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#include <GLFW/glfw3.h>
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namespace Gedeng {
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// A simple 2x2 quad mesh consisting of two triangles. Oriented upwards by default.
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class QuadMesh : public Spatial {
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public:
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QuadMesh(float scale = 1.0f) {
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// Positions
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glm::vec3 pos1 = glm::vec3(-1.0f, 0.0f, 1.0f) * scale;
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glm::vec3 pos2 = glm::vec3(-1.0f, 0.0f, -1.0f) * scale;
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glm::vec3 pos3 = glm::vec3(1.0f, 0.0f, -1.0f) * scale;
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glm::vec3 pos4 = glm::vec3(1.0f, 0.0f, 1.0f) * scale;
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// Texture coordinates
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glm::vec2 uv1 = glm::vec2(0.0f, 1.0f) * scale;
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glm::vec2 uv2 = glm::vec2(0.0f, 0.0f) * scale;
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glm::vec2 uv3 = glm::vec2(1.0f, 0.0f) * scale;
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glm::vec2 uv4 = glm::vec2(1.0f, 1.0f) * scale;
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// Normal vector
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glm::vec3 nm(0.0f, 1.0f, 0.0f);
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// Calculate tangent/bitangent vectors of both triangles
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glm::vec3 tangent1, bitangent1;
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glm::vec3 tangent2, bitangent2;
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// Triangle 1
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glm::vec3 edge1 = pos2 - pos1;
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glm::vec3 edge2 = pos3 - pos1;
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glm::vec2 deltaUV1 = uv2 - uv1;
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glm::vec2 deltaUV2 = uv3 - uv1;
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float f = 1.0f / (deltaUV1.x * deltaUV2.y - deltaUV2.x * deltaUV1.y);
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tangent1.x = f * (deltaUV2.y * edge1.x - deltaUV1.y * edge2.x);
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tangent1.y = f * (deltaUV2.y * edge1.y - deltaUV1.y * edge2.y);
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tangent1.z = f * (deltaUV2.y * edge1.z - deltaUV1.y * edge2.z);
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tangent1 = glm::normalize(tangent1);
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bitangent1.x = f * (-deltaUV2.x * edge1.x + deltaUV1.x * edge2.x);
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bitangent1.y = f * (-deltaUV2.x * edge1.y + deltaUV1.x * edge2.y);
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bitangent1.z = f * (-deltaUV2.x * edge1.z + deltaUV1.x * edge2.z);
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bitangent1 = glm::normalize(bitangent1);
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// Triangle 2
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edge1 = pos3 - pos1;
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edge2 = pos4 - pos1;
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deltaUV1 = uv3 - uv1;
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deltaUV2 = uv4 - uv1;
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f = 1.0f / (deltaUV1.x * deltaUV2.y - deltaUV2.x * deltaUV1.y);
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tangent2.x = f * (deltaUV2.y * edge1.x - deltaUV1.y * edge2.x);
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tangent2.y = f * (deltaUV2.y * edge1.y - deltaUV1.y * edge2.y);
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tangent2.z = f * (deltaUV2.y * edge1.z - deltaUV1.y * edge2.z);
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tangent2 = glm::normalize(tangent2);
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bitangent2.x = f * (-deltaUV2.x * edge1.x + deltaUV1.x * edge2.x);
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bitangent2.y = f * (-deltaUV2.x * edge1.y + deltaUV1.x * edge2.y);
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bitangent2.z = f * (-deltaUV2.x * edge1.z + deltaUV1.x * edge2.z);
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bitangent2 = glm::normalize(bitangent2);
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float quadVertices[] = {// positions // normal // texcoords // tangent // bitangent
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pos1.x, pos1.y, pos1.z, nm.x, nm.y, nm.z, uv1.x,
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uv1.y, tangent1.x, tangent1.y, tangent1.z, bitangent1.x, bitangent1.y, bitangent1.z,
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pos2.x, pos2.y, pos2.z, nm.x, nm.y, nm.z, uv2.x,
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uv2.y, tangent1.x, tangent1.y, tangent1.z, bitangent1.x, bitangent1.y, bitangent1.z,
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pos3.x, pos3.y, pos3.z, nm.x, nm.y, nm.z, uv3.x,
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uv3.y, tangent1.x, tangent1.y, tangent1.z, bitangent1.x, bitangent1.y, bitangent1.z,
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pos1.x, pos1.y, pos1.z, nm.x, nm.y, nm.z, uv1.x,
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uv1.y, tangent2.x, tangent2.y, tangent2.z, bitangent2.x, bitangent2.y, bitangent2.z,
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pos3.x, pos3.y, pos3.z, nm.x, nm.y, nm.z, uv3.x,
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uv3.y, tangent2.x, tangent2.y, tangent2.z, bitangent2.x, bitangent2.y, bitangent2.z,
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pos4.x, pos4.y, pos4.z, nm.x, nm.y, nm.z, uv4.x,
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uv4.y, tangent2.x, tangent2.y, tangent2.z, bitangent2.x, bitangent2.y, bitangent2.z};
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// Configure plane VAO
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glGenVertexArrays(1, &quadVAO);
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glGenBuffers(1, &quadVBO);
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glBindVertexArray(quadVAO);
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glBindBuffer(GL_ARRAY_BUFFER, quadVBO);
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glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(float), (void *)0);
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glEnableVertexAttribArray(1);
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glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(float), (void *)(3 * sizeof(float)));
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glEnableVertexAttribArray(2);
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glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 14 * sizeof(float), (void *)(6 * sizeof(float)));
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glEnableVertexAttribArray(3);
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glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(float), (void *)(8 * sizeof(float)));
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glEnableVertexAttribArray(4);
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glVertexAttribPointer(4, 3, GL_FLOAT, GL_FALSE, 14 * sizeof(float), (void *)(11 * sizeof(float)));
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}
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void render(Shader &shader) {
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shader.setMat4("model", get_matrix());
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glBindVertexArray(quadVAO);
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glDrawArrays(GL_TRIANGLES, 0, 6);
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glBindVertexArray(0);
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}
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private:
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unsigned int quadVAO = 0;
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unsigned int quadVBO;
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};
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} // namespace Gedeng
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