CMakeLists.txt
cmake_minimum_required(VERSION 3.5)
project(glsl_sample)
set(CMAKE_C_STANDARD 99)
add_executable(glsl_sample main.c)
find_package(OpenGL REQUIRED)
include_directories("C:/msys64/mingw64/include/stb")
include_directories(${OPENGL_INCLUDE_DIRS})
# MSYS2パス用のヒント（MINGW64環境）
include_directories("C:/msys64/mingw64/include")
link_directories("C:/msys64/mingw64/lib")
target_link_libraries(glsl_sample glfw3 glew32 opengl32 gdi32)
main.c
#include <stdio.h>
#include <stdlib.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#define STB_IMAGE_IMPLEMENTATION
#include <stb_image.h>
char* load_shader_source(const char* filepath) {
FILE* file = fopen(filepath, "rb");
if (!file) {
fprintf(stderr, "Failed to open %s\n", filepath);
exit(1);
}
fseek(file, 0, SEEK_END);
long len = ftell(file);
rewind(file);
char* buffer = (char*)malloc(len + 1);
fread(buffer, 1, len, file);
buffer[len] = '\0';
fclose(file);
return buffer;
}
GLuint compile_shader(GLenum type, const char* source) {
GLuint shader = glCreateShader(type);
glShaderSource(shader, 1, &source, NULL);
glCompileShader(shader);
GLint success;
glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
if (!success) {
char infoLog[512];
glGetShaderInfoLog(shader, 512, NULL, infoLog);
fprintf(stderr, "Shader compile error: %s\n", infoLog);
exit(1);
}
return shader;
}
int main() {
if (!glfwInit()) {
fprintf(stderr, "GLFW init failed\n");
return -1;
}
GLFWwindow* window = glfwCreateWindow(800, 600, "GLSL Sample", NULL, NULL);
if (!window) {
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glewInit();
char* vertexSource = load_shader_source("../shader.vert");
char* fragmentSource = load_shader_source("../shader.frag");
GLuint vertexShader = compile_shader(GL_VERTEX_SHADER, vertexSource);
GLuint fragmentShader = compile_shader(GL_FRAGMENT_SHADER, fragmentSource);
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glUseProgram(shaderProgram);
GLint mouseLoc = glGetUniformLocation(shaderProgram, "u_mouse");
GLint timeLoc = glGetUniformLocation(shaderProgram, "u_time");
GLint resLoc = glGetUniformLocation(shaderProgram, "u_resolution");
glUniform1i(glGetUniformLocation(shaderProgram, "u_texture"), 0);
float vertices[] = {
// x, y, u, v
-1.0f, 1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 1.0f, 1.0f,
1.0f, -1.0f, 1.0f, 0.0f,
-1.0f, -1.0f, 0.0f, 0.0f
};
unsigned int indices[] = {
0, 1, 2,
2, 3, 0
};
GLuint VAO, VBO, EBO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
glEnableVertexAttribArray(1);
int width, height, nrChannels;
unsigned char *data = stbi_load("../texture.png", &width, &height, &nrChannels, 0);
if (!data) {
fprintf(stderr, "Failed to load texture\n");
return -1;
}
GLuint texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
GLenum format = (nrChannels == 4) ? GL_RGBA : GL_RGB;
glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
stbi_image_free(data);
while (!glfwWindowShouldClose(window)) {
float timeValue = (float)glfwGetTime();
int winW, winH;
double mouseX, mouseY;
glfwGetCursorPos(window, &mouseX, &mouseY);
glfwGetWindowSize(window, &winW, &winH);
mouseX = mouseX/winW;
mouseY = mouseY/winH;
glClearColor(0.1f, 0.1f, 0.15f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderProgram);
glUniform1f(timeLoc, timeValue);
glUniform2f(mouseLoc, (float)mouseX, (float)mouseY);
glUniform2f(resLoc, (float)winW, (float)winH);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glfwSwapBuffers(window);
glfwPollEvents();
}
glDeleteProgram(shaderProgram);
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
glfwTerminate();
return 0;
}
shader.vert
#version 330 core
layout(location = 0) in vec2 aPos;
layout(location = 1) in vec2 aTexCoord;
out vec2 vTexCoord;
void main() {
gl_Position = vec4(aPos, 0.0, 1.0);
vTexCoord = aTexCoord;
}shader.frag
#version 330 core
out vec4 fragColor;
uniform vec2 u_resolution;
uniform float u_time;
// Signed Distance for Torus
float sdTorus(vec3 p, vec2 t) {
vec2 q = vec2(length(p.xz) - t.x, p.y);
return length(q) - t.y;
}
// シーン全体の SDF（ここではトーラスのみ）
float map(vec3 p) {
return sdTorus(p, vec2(0.6, 0.2));
}
// 法線（数値微分）
vec3 getNormal(vec3 p) {
float eps = 0.0005;
return normalize(vec3(
map(p + vec3(eps,0,0)) - map(p - vec3(eps,0,0)),
map(p + vec3(0,eps,0)) - map(p - vec3(0,eps,0)),
map(p + vec3(0,0,eps)) - map(p - vec3(0,0,eps))
));
}
// レイマーチング本体
float raymarch(vec3 ro, vec3 rd) {
float t = 0.0;
for (int i = 0; i < 128; i++) {
float d = map(ro + rd * t);
if (d < 0.001) break;
t += d;
if (t > 20.0) break;
}
return t;
}
void main() {
// 画面座標 → 正規化デバイス空間
vec2 uv = (gl_FragCoord.xy - 0.5 * u_resolution) / u_resolution.y;
// カメラ設定：斜め上方から原点を見る
vec3 ro = vec3(2.0, 1.5, 2.0); // カメラ位置
vec3 ta = vec3(0.0, 0.0, 0.0); // 注視点（原点）
vec3 up = vec3(0.0, 1.0, 0.0); // 上方向ベクトル
// カメラ座標系の計算
vec3 f = normalize(ta - ro);
vec3 r = normalize(cross(f, up));
vec3 u = cross(r, f);
vec3 rd = normalize(r * uv.x + u * uv.y + f);
// レイマーチングで交差距離を取得
float t = raymarch(ro, rd);
vec3 col;
if (t < 20.0) {
// ヒット時のライティング
vec3 p = ro + rd * t;
vec3 normal = getNormal(p);
vec3 lightDir = normalize(vec3(-0.5, 0.8, -0.3));
float diff = clamp(dot(normal, lightDir), 0.0, 1.0);
col = vec3(0.8, 0.6, 0.3) * diff; // トーラス本体の色
}
else {
// 背景色
col = vec3(0.1, 0.1, 0.15);
}
fragColor = vec4(col, 1.0);
}cmd
$ cd c:
furcr@furcraea_built MINGW64 /c
$ cd glsl_sample
furcr@furcraea_built MINGW64 /c/glsl_sample
$ cd glsl_sample_201_3texture
furcr@furcraea_built MINGW64 /c/glsl_sample/glsl_sample_201_3texture
$ cd build
furcr@furcraea_built MINGW64 /c/glsl_sample/glsl_sample_201_3texture/build
$ cmake -G "MSYS Makefiles" ..
CMake Deprecation Warning at CMakeLists.txt:1 (cmake_minimum_required):
Compatibility with CMake < 3.10 will be removed from a future version of
CMake.
Update the VERSION argument <min> value. Or, use the <min>...<max> syntax
to tell CMake that the project requires at least <min> but has been updated
to work with policies introduced by <max> or earlier.
-- The C compiler identification is GNU 15.1.0
-- The CXX compiler identification is GNU 15.1.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/msys64/mingw64/bin/cc.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/msys64/mingw64/bin/c++.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found OpenGL: opengl32
-- Configuring done (2.4s)
-- Generating done (0.0s)
-- Build files have been written to: C:/glsl_sample/glsl_sample_201_3texture/build
furcr@furcraea_built MINGW64 /c/glsl_sample/glsl_sample_201_3texture/build
$ make
[ 50%] Building C object CMakeFiles/glsl_sample.dir/main.c.obj
[100%] Linking C executable glsl_sample.exe
[100%] Built target glsl_sample
furcr@furcraea_built MINGW64 /c/glsl_sample/glsl_sample_201_3texture/build
$ ./glsl_sample
