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-rw-r--r--gl-vfog/CMakeLists.txt9
-rw-r--r--gl-vfog/fs.glsl111
-rw-r--r--gl-vfog/geometry.hh108
-rw-r--r--gl-vfog/main.cc281
-rw-r--r--gl-vfog/vs.glsl12
5 files changed, 0 insertions, 521 deletions
diff --git a/gl-vfog/CMakeLists.txt b/gl-vfog/CMakeLists.txt
deleted file mode 100644
index e085e04..0000000
--- a/gl-vfog/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-cmake_minimum_required(VERSION 3.15 FATAL_ERROR)
-project(gl-vfog CXX)
-
-set(DEMO_NEEDS_DEAR_IMGUI TRUE)
-set(DEMO_NEEDS_SDL3 TRUE)
-include("${CMAKE_CURRENT_LIST_DIR}/../common/c_cpp/CMakeLists.txt")
-
-add_executable(gl-vfog main.cc)
-target_link_libraries(gl-vfog PRIVATE common) \ No newline at end of file
diff --git a/gl-vfog/fs.glsl b/gl-vfog/fs.glsl
deleted file mode 100644
index 12f32b9..0000000
--- a/gl-vfog/fs.glsl
+++ /dev/null
@@ -1,111 +0,0 @@
-#version 330 core
-
-in vec3 f_p;
-
-out vec4 f_color;
-
-// -----------------------------------------------------------------------------
-// Uniforms
-// -----------------------------------------------------------------------------
-uniform vec3 u_cam;
-uniform float u_time;
-uniform int u_mode;
-uniform float u_sigma;
-uniform int u_steps;
-
-// -----------------------------------------------------------------------------
-// Ray-AABB intersection
-// ref: https://tavianator.com/2022/ray_box_boundary.html
-// -----------------------------------------------------------------------------
-bool intersect(vec3 ro, vec3 rd, vec3 bbmin, vec3 bbmax, out float t0, out float t1)
-{
- vec3 inv = 1.0f / rd;
- vec3 ta = (bbmin - ro) * inv;
- vec3 tb = (bbmax - ro) * inv;
- vec3 tmin = min(ta, tb);
- vec3 tmax = max(ta, tb);
- t0 = max(max(tmin.x, tmin.y), tmin.z);
- t1 = min(min(tmax.x, tmax.y), tmax.z);
- return t1 >= max(t0, 0.0f);
-}
-
-// -----------------------------------------------------------------------------
-// Mode 0: Basic volumetric fog
-// -----------------------------------------------------------------------------
-float sample_basic(vec3 pos)
-{
- return 1.0;
-}
-
-// -----------------------------------------------------------------------------
-// Mode 1: Fade along y axis
-// -----------------------------------------------------------------------------
-
-float sample_vfade(vec3 pos)
-{
- return 1.0f - pos.y;
-}
-
-// -----------------------------------------------------------------------------
-// Mode 2: Some waves
-// -----------------------------------------------------------------------------
-
-float sample_waves(vec3 pos)
-{
- // Fractal sum
- // ref: https://thebookofshaders.com/13/
- float h = 0.75f; // baseline
-
- // Big waves
- h += 0.08f * sin(pos.x * 2.0f + u_time);
- h += 0.08f * cos(pos.z * 2.0f + u_time * -1.1f);
-
- // Medium waves
- h += 0.05f * sin(pos.x * 5.0f + u_time * 1.7f);
- h += 0.05f * cos(pos.z * 4.0f + u_time * -2.0f);
-
- // Small but choppy waves
- h += 0.03f * sin(pos.x * 12.0f + u_time * 3.3f);
- h += 0.03f * cos(pos.z * 11.0f + u_time * -2.5f);
-
- return float(pos.y < h);
-}
-
-void main()
-{
- vec3 bbmin = vec3(0.0f, 0.0f, 0.0f);
- vec3 bbmax = vec3(1.0f, 1.0f, 1.0f);
-
- vec3 ro = u_cam;
- vec3 rd = normalize(f_p - ro);
-
- float t0 = 0.0f;
- float t1 = 0.0f;
- if (!intersect(ro, rd, bbmin, bbmax, t0, t1)) {
- f_color = vec4(0.0f, 0.0f, 0.0f, 0.0f);
- return;
- }
-
- // Clamp entry point in front of camera
- float t_enter = max(t0, 0.0f);
- float t_exit = t1;
- float t_len = max(0.0f, t_exit - t_enter);
-
- float density = 0;
- for (int i = 0; i < u_steps; ++i) {
- float t = mix(t_enter, t_exit, (float(i) + 0.5f) / float(u_steps));
- vec3 p = ro + rd * t;
- switch (u_mode) {
- case 0: { density += sample_basic(p); } break;
- case 1: { density += sample_vfade(p); } break;
- case 2: { density += sample_waves(p); } break;
- }
- }
- density /= float(u_steps);
-
- // Beer-Lambert attenuation
- // ref: https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law
- float a = 1.0f - exp(-u_sigma * t_len * density);
-
- f_color = vec4(vec3(1.0f), a);
-}
diff --git a/gl-vfog/geometry.hh b/gl-vfog/geometry.hh
deleted file mode 100644
index c48248a..0000000
--- a/gl-vfog/geometry.hh
+++ /dev/null
@@ -1,108 +0,0 @@
-#ifndef _GEOMETRY_HH_
-#define _GEOMETRY_HH_
-
-#include <cmath>
-
-static inline float Radians(float degrees)
-{
- return degrees * M_PI / 180.0f;
-}
-
-class Vec3
-{
-public:
- float x;
- float y;
- float z;
-public:
- Vec3(float x, float y, float z)
- : x(x), y(y), z(z) { }
-
- inline Vec3 operator+(const Vec3& rhs) const { return Vec3(x + rhs.x, y + rhs.y, z + rhs.z); }
- inline Vec3 operator-(const Vec3& rhs) const { return Vec3(x - rhs.x, y - rhs.y, z - rhs.z); }
-
- inline float* Base() { return &x; }
-
- inline float Length() { return std::sqrtf(x * x + y * y + z * z); }
-
- inline Vec3 Normalize()
- {
- float l = Length();
- if (l < 0.0f) { l = 1.0f; }
- return Vec3(x / l, y / l, z / l);
- }
-
- inline float Dot(const Vec3& rhs)
- {
- return x * rhs.x + y * rhs.y + z * rhs.z;
- }
-
- inline Vec3 Cross(const Vec3& rhs)
- {
- return Vec3(
- y * rhs.z - z * rhs.y,
- z * rhs.x - x * rhs.z,
- x * rhs.y - y * rhs.x
- );
- }
-};
-
-class Mat4x4
-{
-private:
- float m[4 * 4];
-public:
- inline float& operator[](std::size_t s) { return m[s]; }
- inline float operator[](std::size_t s) const { return m[s]; }
-
- inline float* Base() { return m; }
-
- inline Mat4x4 operator*(const Mat4x4& rhs)
- {
- Mat4x4 r = { };
- for (int col = 0; col < 4; ++col) {
- for (int row = 0; row < 4; ++row) {
- r[col * 4 + row] =
- m[0 * 4 + row] * rhs[col * 4 + 0] +
- m[1 * 4 + row] * rhs[col * 4 + 1] +
- m[2 * 4 + row] * rhs[col * 4 + 2] +
- m[3 * 4 + row] * rhs[col * 4 + 3];
- }
- }
- return r;
- }
-public:
- static Mat4x4 LookAt(const Vec3& eye, const Vec3& at, const Vec3& up)
- {
- Vec3 f = (at - eye).Normalize();
- Vec3 s = f.Cross(up).Normalize();
- Vec3 u = s.Cross(f);
- Vec3 t = Vec3(-s.Dot(eye), -u.Dot(eye), f.Dot(eye));
-
- Mat4x4 m;
- m[ 0] = s.x; m[ 1] = u.x; m[ 2] = -f.x; m[ 3] = 0.0f;
- m[ 4] = s.y; m[ 5] = u.y; m[ 6] = -f.y; m[ 7] = 0.0f;
- m[ 8] = s.z; m[ 9] = u.z; m[10] = -f.z; m[11] = 0.0f;
- m[12] = t.x; m[13] = t.y; m[14] = t.z; m[15] = 1.0f;
-
- return m;
- }
-
- static Mat4x4 Perspective(float fov_deg, float aspect, float z_near, float z_far)
- {
- const float fov_cot = 1.0f / std::tanf(Radians(fov_deg) / 2.0f);
-
- Mat4x4 m = { };
-
- m[0*4+0] = fov_cot / aspect;
- m[1*4+1] = fov_cot;
- m[2*4+3] = -1.0f;
-
- m[2*4+2] = (z_far + z_near) / (z_near - z_far);
- m[3*4+2] = (2.0f * z_near * z_far) / (z_near - z_far);
-
- return m;
- }
-};
-
-#endif // _GEOMETRY_HH_
diff --git a/gl-vfog/main.cc b/gl-vfog/main.cc
deleted file mode 100644
index 679d4ec..0000000
--- a/gl-vfog/main.cc
+++ /dev/null
@@ -1,281 +0,0 @@
-// OpenGL volumetric fog demo
-//
-// SPDX-License-Identifier: 0BSD
-//
-// Changelog:
-// - 11/13/25: Initial release
-//
-
-#define GLAD_GL_IMPLEMENTATION
-#include "../common/c_cpp/thirdparty/glad33/glad33.h"
-
-#include <SDL3/SDL.h>
-#include <SDL3/SDL_main.h>
-#include <SDL3/SDL_opengl.h>
-
-#define IMGUI_IMPL_OPENGL_LOADER_CUSTOM
-#include "imgui.h"
-#include "imgui_impl_opengl3.cpp"
-#include "imgui_impl_sdl3.cpp"
-
-#include "geometry.hh"
-
-// Helper: Report errors via glGetError() after every OpenGL function call.
-// macOS does not support glDebugMessageCallback
-static void assert_gl_error(GLenum error, const char* expr, int line)
-{
- if (error != GL_NO_ERROR) {
- const char* error_string;
- switch (error) {
-#define BIND_ERROR(name) case name: { error_string = #name; }; break;
- BIND_ERROR(GL_INVALID_ENUM);
- BIND_ERROR(GL_INVALID_VALUE);
- BIND_ERROR(GL_INVALID_OPERATION);
- BIND_ERROR(GL_INVALID_FRAMEBUFFER_OPERATION);
- BIND_ERROR(GL_OUT_OF_MEMORY);
-#undef BIND_ERROR
- default: SDL_assert(0 && "Invalid GL_ERROR enum");
- }
- SDL_Log("[Line #%u] %s caused %s\n", line, expr, error_string);
- }
-}
-#define GL(expr) \
- expr; \
- for (GLenum _glcode; (_glcode = glGetError()) != GL_NO_ERROR; ) { \
- assert_gl_error(_glcode, #expr, __LINE__); \
- }
-
-int main(int argc, char* argv[])
-{
- (void)argc;
- (void)argv;
-
- if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS)) {
- fprintf(stderr, "Failed to initialize SDL: %s\n", SDL_GetError());
- return EXIT_FAILURE;
- }
-
- SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
- SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
- SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
- SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
- SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
-
- SDL_Window* wnd = SDL_CreateWindow("gl-vfog", 1024, 768, SDL_WINDOW_OPENGL);
- if (!wnd) {
- fprintf(stderr, "Failed to create window: %s\n", SDL_GetError());
- return EXIT_FAILURE;
- }
-
- if (!SDL_GL_CreateContext(wnd)) {
- fprintf(stderr, "Failed to create OpenGL context: %s\n", SDL_GetError());
- return EXIT_FAILURE;
- }
- SDL_GL_SetSwapInterval(1);
-
- if (!gladLoadGL(SDL_GL_GetProcAddress)) {
- fprintf(stderr, "Failed to load OpenGL functions\n");
- return EXIT_FAILURE;
- }
-
- IMGUI_CHECKVERSION();
- ImGui::CreateContext();
- ImGui_ImplSDL3_Init(wnd, 0, 0);
- ImGui_ImplOpenGL3_Init();
- ImGui::GetIO().IniFilename = NULL;
-
- //
- // 0 1
- // +------------+
- // /| /|
- // 4 / | 5 / |
- // +------------+ |
- // | | | |
- // | | 3 | | 2
- // | +---------|--+
- // | / | /
- // 7 |/ 6 |/
- // +------------+
- //
-
- const float vdata[] = {
- 0.0f, 1.0f, 0.0f,
- 1.0f, 1.0f, 0.0f,
- 1.0f, 0.0f, 0.0f,
- 0.0f, 0.0f, 0.0f,
- 0.0f, 1.0f, 1.0f,
- 1.0f, 1.0f, 1.0f,
- 1.0f, 0.0f, 1.0f,
- 0.0f, 0.0f, 1.0f,
- };
-
- const uint16_t idata[] = {
- 1, 0, 3,
- 1, 3, 2,
- 5, 1, 2,
- 5, 2, 6,
- 4, 5, 6,
- 4, 6, 7,
- 0, 4, 7,
- 0, 7, 3,
- 0, 1, 5,
- 0, 5, 4,
- 7, 6, 2,
- 7, 2, 3,
- };
-
- GLuint vao;
- GL(glGenVertexArrays(1, &vao))
- GL(glBindVertexArray(vao));
-
- GLuint vbo;
- GL(glGenBuffers(1, &vbo));
- GL(glBindBuffer(GL_ARRAY_BUFFER, vbo));
- GL(glBufferData(GL_ARRAY_BUFFER, sizeof(vdata), vdata, GL_STATIC_DRAW));
-
- GLuint ibo;
- GL(glGenBuffers(1, &ibo));
- GL(glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo));
- GL(glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(idata), idata, GL_STATIC_DRAW));
-
- GL(glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(float) * 3, NULL));
- GL(glEnableVertexAttribArray(0));
-
- struct {
- GLenum type;
- const char* path;
- } shaders[] = {
- { .type = GL_VERTEX_SHADER, .path = "vs.glsl" },
- { .type = GL_FRAGMENT_SHADER, .path = "fs.glsl" },
- };
-
- GLuint prog = GL(glCreateProgram());
- for (size_t i = 0; i < sizeof(shaders) / sizeof(*shaders); ++i) {
- const char* src = (const char*)SDL_LoadFile(shaders[i].path, NULL);
- if (!src) {
- fprintf(stderr, "Failed to load shader %s: %s\n", shaders[i].path, SDL_GetError());
- return EXIT_FAILURE;
- }
-
- GLuint shader = GL(glCreateShader(shaders[i].type));
- GL(glShaderSource(shader, 1, &src, NULL));
- GL(glCompileShader(shader));
- GLint compile_status = 0;
- GL(glGetShaderiv(shader, GL_COMPILE_STATUS, &compile_status));
- if (compile_status != GL_TRUE) {
- char error[1024] = { 0 };
- GL(glGetShaderInfoLog(shader, sizeof(error), NULL, error));
- SDL_Log("Error compiling shader %s: %s\n", shaders[i].path, error);
- return EXIT_FAILURE;
- }
- GL(glAttachShader(prog, shader));
- }
- GL(glLinkProgram(prog));
-
- GLint prog_status;
- GL(glGetProgramiv(prog, GL_LINK_STATUS, &prog_status));
- if (prog_status != GL_TRUE) {
- char error[1024] = { 0 };
- GL(glGetProgramInfoLog(prog, sizeof(error), NULL, error));
- SDL_Log("Error linking program: %s\n", error);
- return EXIT_FAILURE;
- }
-
- GL(glUseProgram(prog));
-
- GLuint u_view = GL(glGetUniformLocation(prog, "u_view"));
- GLuint u_cam = GL(glGetUniformLocation(prog, "u_cam"));
- GLuint u_time = GL(glGetUniformLocation(prog, "u_time"));
- GLuint u_mode = GL(glGetUniformLocation(prog, "u_mode"));
- GLuint u_sigma = GL(glGetUniformLocation(prog, "u_sigma"));
- GLuint u_steps = GL(glGetUniformLocation(prog, "u_steps"));
-
- bool running = true;
- while (running) {
- SDL_Event evt = { 0 };
- while (SDL_PollEvent(&evt)) {
- ImGui_ImplSDL3_ProcessEvent(&evt);
- switch (evt.type) {
- case SDL_EVENT_QUIT: {
- running = false;
- } break;
- }
- }
-
- int wnd_x = 0;
- int wnd_y = 0;
- SDL_GetWindowSizeInPixels(wnd, &wnd_x, &wnd_y);
-
- ImGui_ImplSDL3_NewFrame();
- ImGui_ImplOpenGL3_NewFrame();
- ImGui::NewFrame();
-
- // Controls
- static int c_mode = 0;
- static float c_sigma = 4.0f;
- static float c_zoom = 1.5f;
- static int c_steps = 64;
- ImGui::SetNextWindowPos(ImVec2(15, 15));
- ImGui::SetNextWindowSize(ImVec2(150, 768 - 30));
- if (ImGui::Begin("Controls", NULL, ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize)) {
- ImGui::SeparatorText("Controls");
- ImGui::DragFloat("Zoom", &c_zoom, 0.05f, 0.1f, 3.0f);
- ImGui::SeparatorText("Settings");
- const char* modes[] = { "Basic", "Fade", "Waves", };
- if (ImGui::BeginCombo("Mode", modes[c_mode])) {
- for (int i = 0; i < IM_ARRAYSIZE(modes); ++i) {
- if (ImGui::Selectable(modes[i], i == c_mode)) {
- c_mode = i;
- }
- }
- ImGui::EndCombo();
- }
- ImGui::DragInt("Steps", &c_steps);
- ImGui::DragFloat("Sigma", &c_sigma, 0.05);
- ImGui::End();
- }
-
- GL(glViewport(0, 0, wnd_x, wnd_y));
- GL(glEnable(GL_CULL_FACE));
- GL(glCullFace(GL_FRONT));
- GL(glEnable(GL_DEPTH_TEST));
- GL(glEnable(GL_BLEND));
- GL(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
- GL(glClearColor(0.1f, 0.1f, 0.1f, 1.0f));
- GL(glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT));
-
- const float t = SDL_GetTicks() / 1e3f;
- const float camt = t * 0.33f;
-
- Vec3 eye = Vec3(0.0f, 1.5f, 0.0f);
- Vec3 tgt = Vec3(0.5f, 0.5f, 0.5f);
- eye.x = tgt.x + SDL_sinf(camt) * c_zoom;
- eye.z = tgt.z + SDL_cosf(camt) * c_zoom;
- Vec3 up = Vec3(0.0f, 1.0f, 0.0f);
-
- Mat4x4 look = Mat4x4::LookAt(eye, tgt, up);
- Mat4x4 proj = Mat4x4::Perspective(70.0f, (float)wnd_x / (float)wnd_y, 0.1f, 10.0f);
- Mat4x4 view = proj * look;
-
- GL(glUniformMatrix4fv(u_view, 1, GL_FALSE, view.Base()))
- GL(glUniform3fv(u_cam, 1, eye.Base()));
- GL(glUniform1f(u_time, t));
- GL(glUniform1i(u_mode, c_mode));
- GL(glUniform1f(u_sigma, c_sigma));
- GL(glUniform1i(u_steps, c_steps));
-
- GL(glDrawElements(GL_TRIANGLES, 3 * 12, GL_UNSIGNED_SHORT, NULL));
-
- ImGui::Render();
- ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
-
- if (!SDL_GL_SwapWindow(wnd)) {
- fprintf(stderr, "Failed to present window: %s", SDL_GetError());
- return EXIT_FAILURE;
- }
- }
-
- SDL_DestroyWindow(wnd);
-
- return EXIT_SUCCESS;
-}
diff --git a/gl-vfog/vs.glsl b/gl-vfog/vs.glsl
deleted file mode 100644
index bf8c8eb..0000000
--- a/gl-vfog/vs.glsl
+++ /dev/null
@@ -1,12 +0,0 @@
-#version 330 core
-
-layout (location = 0) in vec3 v_p;
-
-out vec3 f_p;
-
-uniform mat4 u_view;
-
-void main() {
- f_p = v_p;
- gl_Position = u_view * vec4(v_p, 1.0f);
-} \ No newline at end of file
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