Add a shader program registry

src/client/client_imgui.cpp

@@ -106,6 +106,8 @@ int main(int argc, char** argv)
     const char* shader_list = "shaders/list.txt";
     static struct ShaderRegistry shader_registry;
     loadShadersFromFile(shader_list, &shader_registry);
+    static std::vector<RegisteredShaderProgram> shader_program_registry;
+    loadShaderProgramsFromFile("shaders/shader_programs.txt", &shader_registry, &shader_program_registry);
     messager.registerCallback(&debug_messagebus_callback);
     while(!glfwWindowShouldClose(window)) {
        glfwPollEvents();

src/common/shaderloader.hpp

@@ -7,11 +7,13 @@
 #include <stdlib.h>
 #include <sstream>
 #include <unistd.h>
+#include <vector>
 
 #include <glad/glad.h>
 #include <GLFW/glfw3.h>
 
 enum ShaderType {
+   invalid = 0,
    vertex = GL_VERTEX_SHADER,
    fragment = GL_FRAGMENT_SHADER,
    geometry = GL_GEOMETRY_SHADER,
@@ -26,10 +28,21 @@ struct RegisteredShader {
    GLuint shaderID;
 } RegisteredShader;
 
-struct RegisteredShaderProgram {
+class RegisteredShaderProgram {
    char *programName;
    GLuint programID;
-} RegisteredShaderProgram;
+public:
+   RegisteredShaderProgram(char *name, GLuint programID) {
+      int name_size = strlen(name);
+      char *n = (char*) calloc(name_size, sizeof(char));
+      strncpy(n, name, name_size);
+      this->programName = n;
+      this->programID = programID;
+   };
+   ~RegisteredShaderProgram() {
+      free(this->programName);
+   }
+};
 
 struct ShaderRegistry {
    struct RegisteredShader *list = 0;
@@ -62,7 +75,7 @@ struct RegisteredShader* find_shader(struct ShaderRegistry *r, char *name) {
    int i = 0;
    struct RegisteredShader *s = 0;
    for(i; i < r->size; i++) {
-      s = (r->list) + (i * sizeof(struct RegisteredShader));
+      s = &r->list[i];
       if(strcmp(s->shaderName, name) == 0) {
          return s;
       }
@@ -96,10 +109,10 @@ void remove_shader_by_name(struct ShaderRegistry *r, char *name) {
 
 
 
-struct ShaderProgramRegistry {
+class ShaderProgramRegistry {
    struct RegisteredShareProgram *list = 0;
    int size = 0;
-} ShaderProgramRegistry;
+};
 
 
 GLuint compile_shader(const char* file_path, int t) {
@@ -136,10 +149,106 @@ GLuint compile_shader(const char* file_path, int t) {
       glGetShaderInfoLog(shader_id, InfoLogLength, NULL, &error_message[0]);
       printf("%s\n", &error_message[0]);
    }
+   else {
+      printf("compiled shader %d from source %s\n", shader_id, file_path);
+   }
 
    return shader_id;
 }
 
+int loadShaderProgramsFromFile(const char* file_path, struct ShaderRegistry *shader_registry,
+                               std::vector<RegisteredShaderProgram> *program_registry) {
+   FILE *fp;
+   char *line;
+   size_t size = 0;
+   const char *delim = ":";
+   const char *delim2 = ",";
+   fp = fopen(file_path, "r");
+   if (fp == NULL) {
+      return -1;
+   }
+   char *name;
+   char *program_list;
+   char *file_path_copy = (char*) calloc(strlen(file_path), sizeof(char));
+   strncpy(file_path_copy, file_path, strlen(file_path));
+   char *base = dirname((char*) file_path_copy);
+   while((size = getline(&line, &size, fp)) != -1) {
+      if(size == 0) {
+         // Skipping, line length 0
+         continue;
+      }
+      if(line[0] == '#') {
+         // Skipping, line is a comment
+         continue;
+      }
+      char *line_copy = (char*) calloc(size, sizeof(char*));
+      strncpy(line_copy, line, size);
+      printf("%s\n", line_copy);
+
+      // Format <name>,<type>,<filepath>
+      name = strtok(line_copy, delim);
+      program_list = strtok(NULL, delim);
+      printf("%s\n", program_list);
+      if (name == NULL || program_list == NULL) {
+         // Invalid line, not enough elements.
+         // @TODO Inform the user.
+         free(line_copy);
+         name = program_list = NULL;
+         continue;
+      }
+
+      // Start a new Shader Program
+      char *program_list_copy = (char*) calloc(strlen(program_list), sizeof(char));
+      strncpy(program_list_copy, program_list, strlen(program_list));
+      char *new_line_pos = strrchr(program_list_copy, '\n');
+      if (new_line_pos) {
+         new_line_pos[0] = 0;
+      }
+      printf("%s\n", program_list_copy);
+      char *shader_name = strtok(program_list_copy, delim2);
+      char *last_shader_name = NULL;
+      GLuint program = glCreateProgram();
+      GLint Result = GL_FALSE;
+      do {
+         if (last_shader_name != NULL && shader_name == last_shader_name) {
+            shader_name = NULL;
+            break;
+         }
+         printf("sname %s ; last_shader %s\n", shader_name, last_shader_name);
+         struct RegisteredShader *rs = find_shader(shader_registry, shader_name);
+         if (rs == NULL) {
+            // Should this be an error, or a warning?
+            // @TODO Inform the user
+            printf("could not find shader '%s'", shader_name);
+            continue;
+         }
+         printf("linking program %d with shader %d\n", program, rs->shaderID);
+         glAttachShader(program, rs->shaderID);
+         last_shader_name = shader_name;
+         shader_name = strtok(NULL, delim2);
+      }
+      while (shader_name != NULL);
+      glLinkProgram(program);
+      // Check the program
+      int InfoLogLength;
+      glGetProgramiv(program, GL_LINK_STATUS, &Result);
+      glGetProgramiv(program, GL_INFO_LOG_LENGTH, &InfoLogLength);
+      if (InfoLogLength > 0){
+         std::vector<char> ProgramErrorMessage(InfoLogLength+1);
+         glGetProgramInfoLog(program, InfoLogLength, NULL, &ProgramErrorMessage[0]);
+         printf("%s\n", &ProgramErrorMessage[0]);
+      }
+
+      // Add to program_registry
+      if (InfoLogLength == 0) {
+         program_registry->push_back(RegisteredShaderProgram(name, program));
+      }
+      free(program_list_copy);
+      free(line_copy);
+   }
+   return 0;
+}
+
 int loadShadersFromFile(const char* file_path, struct ShaderRegistry *registry) {
    FILE *fp;
    char *line;
@@ -201,10 +310,10 @@ int loadShadersFromFile(const char* file_path, struct ShaderRegistry *registry)
          shader_type = geometry;
       }
       else {
-         shader_type = 0;
+         shader_type = invalid;
       }
 
-      if(shader_type == 0) {
+      if(shader_type == invalid) {
          // Invalid line, unknown type.
          // @TODO Inform the user.
          free(line_copy);

src/shaders/fragmentRed.glsl

@@ -1,5 +1,6 @@
 #version 300 es
-out vec3 color;
+// the precision mediump is required in 3.0es
+out mediump vec3 color;
 void main(){
   color = vec3(1,0,0);
 }