From 2890cf45c1ad62bf8496f15dfb4796f9c71c02eb Mon Sep 17 00:00:00 2001 From: Hunter Kvalevog Date: Thu, 20 Nov 2025 15:37:28 -0600 Subject: shaders --- gl-vfog/CMakeLists.txt | 9 -- gl-vfog/fs.glsl | 111 ------------------- gl-vfog/geometry.hh | 108 ------------------- gl-vfog/main.cc | 281 ------------------------------------------------- gl-vfog/vs.glsl | 12 --- 5 files changed, 521 deletions(-) delete mode 100644 gl-vfog/CMakeLists.txt delete mode 100644 gl-vfog/fs.glsl delete mode 100644 gl-vfog/geometry.hh delete mode 100644 gl-vfog/main.cc delete mode 100644 gl-vfog/vs.glsl (limited to 'gl-vfog') 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 - -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 -#include -#include - -#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 -- cgit v1.2.3