read fragment shader from file

Makefile.am

@@ -2,4 +2,4 @@ AUTOMAKE_OPTIONS = foreign subdir-objects -Wall
 bin_PROGRAMS = forge
 forge_SOURCES = src/main.c src/args.c src/forge.c src/file.c
 forge_CFLAGS = -Ofast -march=native -flto -funroll-loops -fprefetch-loop-arrays -fno-exceptions -fopenmp
-include_HEADERS = src/main.h src/args.h src/config.h src/types.h src/forge.h src/file.h include/linmath.h include/glad/gl.h
+include_HEADERS = src/main.h src/args.h src/config.h src/types.h src/forge.h src/file.h src/constants.h include/linmath.h include/glad/gl.h

README.md

@@ -86,10 +86,11 @@ make -f Makefile.dev release-arch
   - [x] Create GLSL Window
   - [x] Load static fragment shader into GLSL
   - [x] Add default uniforms
-  - [ ] Read fragment shader from file
+  - [x] Read fragment shader from file
   - [ ] Handle compilation errors
-  - [ ] Minimal working fragment sample
-  - [ ] Hot-reload fragment shader
+  - [x] Minimal working fragment sample
+  - [x] Hot-reload fragment shader
+  - [ ] Specify fragment shader path
   - [x] Force fullscreen
   - [x] Select screen as argument / config
 - [ ] Midi

shaders/frag.glsl

@@ -0,0 +1,15 @@
+#version 330
+
+uniform float iTime;
+uniform vec2 iResolution;
+in vec2 vUV;
+out vec4 fragColor;
+
+void main() {
+    vec2 uv0 = vUV.st;
+    float ratio = iResolution.x / iResolution.y;
+    vec2 uv1 = (uv0 - .5) * vec2(ratio, 1);
+    vec3 color = vec3(vUV, sin(iTime * 0.5) * 0.5 + 0.5);
+    color *= 1 - step(cos(iTime) * 0.1 + 0.5,length(uv1));
+    fragColor = vec4(color, 1.0);
+}

src/args.c

@@ -1,10 +1,11 @@
-#include "args.h"
-#include "config.h"
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
+#include "args.h"
+#include "config.h"
+
 void print_help(int status_code) {
   puts(PACKAGE
        " " VERSION "\n\n"

src/constants.h

@@ -0,0 +1,16 @@
+#include "types.h"
+
+static const char *vertex_shader_text =
+    "#version 330\n"
+    "uniform mat4 mvp;\n"
+    "in vec2 vPos;\n"
+    "out vec2 vUV;\n"
+    "void main()\n"
+    "{\n"
+    "    gl_Position = mvp * vec4(vPos, 0.0, 1.0);\n"
+    "    vUV = vPos;\n"
+    "}\n";
+
+static const Vertex vertices[6] = {{{0.0f, 0.0f}}, {{0.0f, 1.0f}},
+                                   {{1.0f, 1.0f}}, {{0.0f, 0.0f}},
+                                   {{1.0f, 1.0f}}, {{1.0f, 0.0f}}};

src/file.c

@@ -23,7 +23,9 @@ bool should_update_file(File *file) {
 
 void update_file(File *file) {
   // free remaining data
-  free(file->content);
+  if (file->content != 0) {
+    free(file->content);
+  }
   // init empty file
   file->content = 0;
   file->error = false;
@@ -56,7 +58,9 @@ void update_file(File *file) {
 }
 
 File read_file(char *path) {
-  File file = {path, 0, 0, 0};
+  File file = {path, 0, false, 0};
   update_file(&file);
   return file;
-}
+}
+
+void free_file(File *file) { free(file->content); }

src/file.h

@@ -9,4 +9,6 @@ bool should_update_file(File *file);
 
 void update_file(File *file);
 
+void free_file(File *file);
+
 #endif

src/forge.c

@@ -1,47 +1,18 @@
-#include "config.h"
-#include "types.h"
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 
-#include <linmath.h>
+#include "config.h"
+#include "constants.h"
+#include "file.h"
+#include "types.h"
 
+#include <linmath.h>
 #define GLAD_GL_IMPLEMENTATION
 #include <glad/gl.h>
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>
 
-static const Vertex vertices[6] = {{{0.0f, 0.0f}}, {{0.0f, 1.0f}},
-                                   {{1.0f, 1.0f}}, {{0.0f, 0.0f}},
-                                   {{1.0f, 1.0f}}, {{1.0f, 0.0f}}};
-
-static const char *vertex_shader_text =
-    "#version 330\n"
-    "uniform mat4 mvp;\n"
-    "in vec2 vPos;\n"
-    "out vec2 vUV;\n"
-    "void main()\n"
-    "{\n"
-    "    gl_Position = mvp * vec4(vPos, 0.0, 1.0);\n"
-    "    vUV = vPos;\n"
-    "}\n";
-
-static const char *fragment_shader_text =
-    "#version 330\n"
-    "uniform float iTime;\n"
-    "uniform vec2 iResolution;\n"
-    "in vec2 vUV;\n"
-    "out vec4 fragColor;\n"
-    "void main()\n"
-    "{\n"
-    "    vec2 uv0 = vUV.st;\n"
-    "    float ratio = iResolution.x / iResolution.y;\n"
-    "    vec2 uv1 = (uv0 - .5) * vec2(ratio, 1);\n"
-    "    vec3 color = vec3(vUV, sin(iTime * 0.5) * 0.5 + 0.5);\n"
-    "    color *= 1 - step(cos(iTime) * 0.5 + 0.5,length(uv1));\n"
-    "    fragColor = vec4(color, 1.0);\n"
-    "}\n";
-
 void error_callback(int error, const char *description) {
   fprintf(stderr, "Error %d: %s\n", error, description);
   glfwTerminate();
@@ -56,6 +27,8 @@ static void key_callback(GLFWwindow *window, int key, int scancode, int action,
   }
 }
 
+// TODO extract to window file
+// TODO split into smaller functions
 void *init_window(GLFWwindow **window, Parameters params) {
   // set errors handler
   glfwSetErrorCallback(error_callback);
@@ -112,8 +85,11 @@ void *init_window(GLFWwindow **window, Parameters params) {
   return window;
 }
 
-ShaderProgram init_program() {
+// TODO extract to "shaders" file
+// TODO split into smaller functions
+ShaderProgram init_program(File fragment_shader) {
   ShaderProgram program = {};
+  GLint status_params;
 
   glGenBuffers(1, &program.vertex_buffer);
   glBindBuffer(GL_ARRAY_BUFFER, program.vertex_buffer);
@@ -123,10 +99,27 @@ ShaderProgram init_program() {
   glShaderSource(program.vertex_shader, 1, &vertex_shader_text, NULL);
   glCompileShader(program.vertex_shader);
 
+  glGetShaderiv(program.vertex_shader, GL_COMPILE_STATUS, &status_params);
+  if (status_params == GL_FALSE) {
+    program.error = true;
+    // TODO use glGetShaderInfoLog( 	GLuint shader, GLsizei
+    // maxLength, GLsizei *length, GLchar *infoLog);
+  }
+
   program.fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
-  glShaderSource(program.fragment_shader, 1, &fragment_shader_text, NULL);
+  glShaderSource(program.fragment_shader, 1,
+                 (const GLchar *const *)&fragment_shader.content, NULL);
   glCompileShader(program.fragment_shader);
 
+  glGetShaderiv(program.fragment_shader, GL_COMPILE_STATUS, &status_params);
+  if (status_params == GL_FALSE) {
+    program.error = true;
+  }
+
+  if (program.error) {
+    return program;
+  }
+
   program.program = glCreateProgram();
   glAttachShader(program.program, program.vertex_shader);
   glAttachShader(program.program, program.fragment_shader);
@@ -146,6 +139,21 @@ ShaderProgram init_program() {
   return program;
 }
 
+// TODO extract to "shaders" file
+void update_program(ShaderProgram program, File fragment_shader) {
+  GLint status_params;
+  glShaderSource(program.fragment_shader, 1,
+                 (const GLchar *const *)&fragment_shader.content, NULL);
+  glCompileShader(program.fragment_shader);
+
+  glGetShaderiv(program.fragment_shader, GL_COMPILE_STATUS, &status_params);
+  if (status_params == GL_FALSE) {
+    fprintf(stderr, "Failed to compile shaders\n"); // TODO add info
+    return;
+  }
+  glLinkProgram(program.program);
+}
+
 void loop(GLFWwindow *window, ShaderProgram program) {
   int width, height;
   glfwGetFramebufferSize(window, &width, &height);
@@ -173,13 +181,32 @@ void loop(GLFWwindow *window, ShaderProgram program) {
 void forge_run(Parameters params) {
   GLFWwindow *window;
 
+  File fragment_shader = read_file("shaders/tmp.glsl");
+
+  if (fragment_shader.error) {
+    fprintf(stderr, "Cannot read file\n");
+    exit(EXIT_FAILURE);
+  }
+
   init_window(&window, params);
 
-  ShaderProgram program = init_program();
+  ShaderProgram program = init_program(fragment_shader);
+
+  if (program.error) {
+    fprintf(stderr, "Failed to compile shaders\n");
+    glfwTerminate();
+    exit(EXIT_FAILURE);
+  }
 
   while (!glfwWindowShouldClose(window)) {
+    if (should_update_file(&fragment_shader)) {
+      update_file(&fragment_shader);
+      update_program(program, fragment_shader);
+    }
     loop(window, program);
   }
 
   glfwTerminate();
+
+  free_file(&fragment_shader);
 }

src/main.c

@@ -1,10 +1,11 @@
-#include "args.h"
-#include "config.h"
-#include "forge.h"
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "args.h"
+#include "config.h"
+#include "forge.h"
+
 int main(int argc, char **argv) {
   Parameters params;
   params = parse_args(argc, argv);

src/types.h

@@ -1,8 +1,9 @@
-#include <glad/gl.h>
-#include <linmath.h>
 #include <stdbool.h>
 #include <time.h>
 
+#include <glad/gl.h>
+#include <linmath.h>
+
 #ifndef TYPES_H
 #define TYPES_H
 
@@ -35,6 +36,8 @@ typedef struct ShaderProgram {
   GLuint ires_location;
 
   GLuint vertex_array;
+
+  bool error;
 } ShaderProgram;
 
 #endif