Commit: 0bf15dc5e7dca2380ac36205fc781de8cc034872
Author: Randy Palamar
Date: Wed, 22 May 2024 19:19:53 -0600
start drawing the thing
Diffstat:
| A | LICENSE | | | 13 | +++++++++++++ |
| A | build.sh | | | 9 | +++++++++ |
| A | frag.glsl | | | 34 | ++++++++++++++++++++++++++++++++++ |
| A | main.c | | | 260 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| A | vert.glsl | | | 9 | +++++++++ |
5 files changed, 325 insertions(+), 0 deletions(-)
diff --git a/LICENSE b/LICENSE
@@ -0,0 +1,13 @@
+© 2024 Randy Palamar <randy@rnpnr.xyz>
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/build.sh b/build.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+set -x
+
+cflags="-march=native -O3 -g3 -Wall "
+cflags="$cflags $(pkg-config --cflags glfw3 gl)"
+ldflags=$(pkg-config --static --libs glfw3 gl)
+
+cc $cflags main.c $ldflags -o mandelbrot
diff --git a/frag.glsl b/frag.glsl
@@ -0,0 +1,34 @@
+/* see LICENSE for licensing details */
+#version 460 core
+
+out vec4 colour;
+
+uniform uvec2 u_screen_dim;
+
+vec2 map_mandelbrot(vec2 v)
+{
+ float x = v.x * 2.47 - 2;
+ float y = v.y * 2.14 - 1.12;
+ return vec2(x, y);
+}
+
+void main()
+{
+ vec2 xy0 = map_mandelbrot(gl_FragCoord.xy / u_screen_dim.xy);
+ colour = vec4(0, 0, 0.1, 1);
+
+ int i;
+ float xx = 0, yy = 0;
+ vec2 xy = xy0;
+ for (i = 0; i < 256 && xx + yy < 4.0; i++) {
+ xx = xy.x * xy.x;
+ yy = xy.y * xy.y;
+ xy = vec2(xx - yy + xy0.x, 2 * xy.x * xy.y + xy0.y);
+ }
+ if (i < 256) {
+ float r = (i >> 0) / 255.0;
+ float g = (i >> 2) / 255.0;
+ float b = (i >> 3) / 255.0;
+ colour = vec4(r, g, b, 1.0);
+ }
+}
diff --git a/main.c b/main.c
@@ -0,0 +1,260 @@
+/* see LICENSE for licensing details */
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <GL/gl.h>
+#include <GLES3/gl32.h>
+#include <GLFW/glfw3.h>
+
+typedef float f32;
+typedef uint8_t u8;
+typedef int32_t i32;
+typedef uint32_t u32;
+typedef ptrdiff_t size;
+
+typedef struct { size len; u8 *data; } s8;
+
+typedef union {
+ struct { u8 a, b, g, r; };
+ u32 rgba;
+} Colour;
+
+static struct {
+ GLFWwindow *window;
+ u32 vao, vbo;
+ i32 pid;
+ i32 height, width;
+ i32 u_screen_dim;
+ Colour clear_colour;
+} g_glctx;
+
+static void
+debug_logger(u32 src, u32 type, u32 id, u32 lvl, i32 len, const char *msg, const void *data)
+{
+ (void)src; (void)type; (void)id; (void)data;
+ fputs("[gl error ", stderr);
+ switch(lvl) {
+ case GL_DEBUG_SEVERITY_HIGH: fputs("HIGH]: ", stderr); break;
+ case GL_DEBUG_SEVERITY_MEDIUM: fputs("MEDIUM]: ", stderr); break;
+ case GL_DEBUG_SEVERITY_LOW: fputs("LOW]: ", stderr); break;
+ default: fputs("(default)]: ", stderr); break;
+ }
+ fwrite(msg, 1, len, stderr);
+ fputc('\n', stderr);
+}
+
+static void
+error_callback(int code, const char *desc)
+{
+ fprintf(stderr, "GLFW Error (0x%04X): %s\n", code, desc);
+}
+
+static void
+fb_callback(GLFWwindow *win, i32 w, i32 h)
+{
+ g_glctx.height = h;
+ g_glctx.width = w;
+ glViewport(0, 0, w, h);
+ if (g_glctx.u_screen_dim != -1)
+ glUniform2ui(g_glctx.u_screen_dim, w, h);
+}
+
+static void
+key_callback(GLFWwindow *win, i32 key, i32 sc, i32 action, i32 mod)
+{
+ (void)sc; (void)mod;
+ if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
+ glfwSetWindowShouldClose(win, GL_TRUE);
+}
+
+static void
+clear_colour(Colour c)
+{
+ glClearColor(c.r / 255.0f, c.b / 255.0f, c.g / 255.0f, c.a / 255.0f);
+ glClear(GL_COLOR_BUFFER_BIT);
+}
+
+static void
+init_renderer(void)
+{
+ glDebugMessageCallback(debug_logger, NULL);
+ glEnable(GL_DEBUG_OUTPUT);
+ glDebugMessageControl(GL_DONT_CARE, GL_DONT_CARE,
+ GL_DEBUG_SEVERITY_NOTIFICATION,
+ 0, 0, GL_FALSE);
+
+ glGenVertexArrays(1, &g_glctx.vao);
+ glBindVertexArray(g_glctx.vao);
+
+ f32 vertices[] = {
+ -1.0f, 1.0f,
+ -1.0f, -1.0f,
+ 1.0f, 1.0f,
+ 1.0f, -1.0f,
+ };
+ glGenBuffers(1, &g_glctx.vbo);
+ glBindBuffer(GL_ARRAY_BUFFER, g_glctx.vbo);
+ glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), &vertices, GL_STATIC_DRAW);
+ glEnableVertexAttribArray(0);
+ glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
+}
+
+static i32
+spawn_window(void)
+{
+ GLFWmonitor *mon = glfwGetPrimaryMonitor();
+ if (!mon)
+ return -1;
+ glfwGetMonitorWorkarea(mon, NULL, NULL, &g_glctx.width, &g_glctx.height);
+
+ glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+ glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
+ glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+
+ g_glctx.window = glfwCreateWindow(g_glctx.width, g_glctx.height,
+ "Mandelbrot Viewer", NULL, NULL);
+ if (g_glctx.window == NULL)
+ return -1;
+
+ glfwMakeContextCurrent(g_glctx.window);
+
+ /* disable vsync */
+ glfwSwapInterval(0);
+
+ glfwSetFramebufferSizeCallback(g_glctx.window, fb_callback);
+ glfwSetKeyCallback(g_glctx.window, key_callback);
+ //glfwSetScrollCallback(glctx.window, scroll_callback);
+
+ g_glctx.clear_colour = (Colour){ .r = 64, .b = 64, .g = 64, .a = 255 };
+ clear_colour(g_glctx.clear_colour);
+
+ init_renderer();
+
+ return 0;
+}
+
+static s8
+read_whole_file(char *file)
+{
+ s8 ret = {0};
+ i32 fd = open(file, O_RDONLY);
+ if (fd < 0)
+ return ret;
+ ret.len = lseek(fd, 0L, SEEK_END);
+ ret.data = malloc(ret.len);
+ lseek(fd, 0L, SEEK_SET);
+ if (ret.data == NULL) {
+ ret.len = 0;
+ close(fd);
+ return ret;
+ }
+ if (ret.len != read(fd, ret.data, ret.len)) {
+ ret.len = 0;
+ free(ret.data);
+ }
+ close(fd);
+ return ret;
+}
+
+static u32
+compile_shader(u32 type, s8 s)
+{
+ u32 sid = glCreateShader(type);
+ glShaderSource(sid, 1, (const char **)&s.data, (int *)&s.len);
+ glCompileShader(sid);
+
+ i32 res = 0;
+ glGetShaderiv(sid, GL_COMPILE_STATUS, &res);
+ if (res != GL_TRUE) {
+ i32 len, len2;
+ glGetShaderiv(sid, GL_INFO_LOG_LENGTH, &len);
+ char *data = malloc(len);
+ glGetShaderInfoLog(sid, len, &len2, data);
+ fputs("compile_shader: ", stderr);
+ fwrite(data, 1, len2, stderr);
+ fputc('\n', stderr);
+ free(data);
+ glDeleteShader(sid);
+ return 0;
+ }
+
+ return sid;
+}
+
+static i32
+program_from_files(char *vert, char *frag)
+{
+ s8 vertex = read_whole_file(vert);
+ s8 fragment = read_whole_file(frag);
+ if (vertex.len == 0 || fragment.len == 0)
+ return -1;
+ i32 pid = glCreateProgram();
+ u32 vid = compile_shader(GL_VERTEX_SHADER, vertex);
+ u32 fid = compile_shader(GL_FRAGMENT_SHADER, fragment);
+
+ if (fid == 0 || vid == 0)
+ return -1;
+
+ glAttachShader(pid, vid);
+ glAttachShader(pid, fid);
+ glLinkProgram(pid);
+ glValidateProgram(pid);
+ glDeleteShader(vid);
+ glDeleteShader(fid);
+ glUseProgram(pid);
+
+ g_glctx.u_screen_dim = glGetUniformLocation(pid, "u_screen_dim");
+ if (g_glctx.u_screen_dim != -1)
+ glUniform2ui(g_glctx.u_screen_dim, g_glctx.width, g_glctx.height);
+
+ free(vertex.data);
+ free(fragment.data);
+
+ return pid;
+}
+
+int
+main(void)
+{
+ if (!glfwInit())
+ return -1;
+ glfwSetErrorCallback(error_callback);
+
+ spawn_window();
+
+ if (g_glctx.window == NULL) {
+ glfwTerminate();
+ return -1;
+ }
+
+ g_glctx.pid = program_from_files("vert.glsl", "frag.glsl");
+ if (g_glctx.pid == -1) {
+ glfwTerminate();
+ return -1;
+ }
+
+ u32 fcount = 0;
+ f32 last_time = 0;
+ while (!glfwWindowShouldClose(g_glctx.window)) {
+ glfwPollEvents();
+
+ f32 current_time = glfwGetTime();
+ f32 dt = current_time - last_time;
+ last_time = current_time;
+ if (++fcount > 1000) {
+ printf("FPS: %0.03f | dt = %0.03f [ms]\n",
+ 1 / dt, dt * 1e3);
+ fcount = 0;
+ }
+
+ clear_colour(g_glctx.clear_colour);
+ glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+ glfwSwapBuffers(g_glctx.window);
+ }
+
+ return 0;
+}
diff --git a/vert.glsl b/vert.glsl
@@ -0,0 +1,9 @@
+/* see LICENSE for licensing details */
+#version 460 core
+
+layout(location = 0) in vec4 position;
+
+void main()
+{
+ gl_Position = position;
+}