WIP: une pause; je vais voir si l'erreur est la même sur opengl_sandbox

src/graphics/shaders_study.c

@@ -0,0 +1,159 @@
+/*
+ *      Gem-graph OpenGL experiments
+ *
+ *      Desc: GL functions
+ *
+ *  Copyright (C) 2023 Arthur Menges <arthur.menges@a-lec.org>
+ *  Copyright (C) 2023 Adrien Bourmault <neox@a-lec.org>
+ *  Copyright (C) 2023 Jean Sirmai <jean@a-lec.org>
+ *
+ *  This file is part of Gem-graph.
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "../../include/base.h"
+#include "../../include/ui.h"
+#include "../../include/graphics.h"
+#include "../../include/shaders_study.h"
+#include "../../include/arrows.h"
+#include "../../include/grid.h"
+
+#define VERTEX_SHADER_FILE "src/shaders/shader.vert"
+#define FRAG_SHADER_FILE "src/shaders/shader.frag"
+
+
+//  Que fait l'instruction suivante (ligne 397 de graphics.c)
+//     dans  "bool graphics_init(const char *gl_area)" ?
+//
+//    if (!graphics_init_shaders(gl_area)) return false;
+//
+//  Et comment et pourquoi cette structure "gl_area_array" ?
+// (Dynamic array of ptrs to dynamically allocated gl_area_entry)
+//
+//      struct gl_area_entry **gl_area_array = NULL;
+
+
+
+/*
+ * Initializes the shaders of a gl_area and link them to a program
+ *
+ * @param   gl_area, ptr to the gl_area widget
+ *
+ * @return  true if initialized
+ */
+bool graphics_init_shaders(const void *gl_area)
+{
+    char *vertex_shader;
+    char *fragment_shader;
+    struct gl_area_entry *entry;
+    int status;
+    GLuint vertex, fragment;
+    GLuint program = 0;
+    GLuint m = 0;
+    GLuint v = 0;
+    GLuint p = 0;
+
+    entry = graphics_find_glarea_from_ptr(gl_area);
+
+    if (entry == NULL) {
+        errno = EFAULT;
+        perror("gl_area_array entry not found");
+        return false;
+    }
+
+    // Load vertex shader file
+    vertex_shader = read_file(VERTEX_SHADER_FILE);
+    if (vertex_shader == NULL)
+        return false;
+    vertex = create_shader(GL_VERTEX_SHADER, vertex_shader);
+
+//  !  WARNING  !  l'instruction suivante (ou un autre 'free') a pu provoquer un 'double free' (Abandon)
+    if(vertex == 0) {
+        entry->program = 0;
+        g_free(vertex_shader);
+        return false;
+    }
+
+    // Load fragment shader file
+    fragment_shader = read_file(FRAG_SHADER_FILE);
+    if (fragment_shader == NULL)
+        return false;
+    fragment = create_shader(GL_FRAGMENT_SHADER, fragment_shader);
+
+    if(fragment == 0) {
+        glDeleteShader(vertex);
+        entry->program = 0;
+        g_free(vertex_shader);
+        g_free(fragment_shader);
+        return false;
+    }
+
+    // Link shaders to program
+    program = glCreateProgram();
+    glAttachShader(program, vertex);
+    glAttachShader(program, fragment);
+
+    glLinkProgram(program);
+
+    glGetProgramiv(program, GL_LINK_STATUS, &status);
+
+    if(status == GL_FALSE) {
+        int log_len;
+        char *buffer;
+
+        glGetProgramiv(program, GL_INFO_LOG_LENGTH, &log_len);
+
+        buffer = g_malloc(log_len + 1);
+        assert(buffer);
+        glGetProgramInfoLog(program, log_len, NULL, buffer);
+
+        g_warning("Linking failure:\n%s", buffer);
+
+        g_free(buffer);
+
+        glDeleteProgram(program);
+        program = 0;
+
+        glDeleteShader(vertex);
+        glDeleteShader(fragment);
+
+        g_free(vertex_shader);
+        g_free(fragment_shader);
+
+        return false;
+    }
+
+    /* Get the location of the "mvp" uniform */
+    m = glGetUniformLocation(program, "model_matrix");
+    v = glGetUniformLocation(program, "view_matrix");
+    p = glGetUniformLocation(program, "projection_matrix");
+
+    glDetachShader(program, vertex);
+    glDetachShader(program, fragment);
+
+    glDeleteShader(vertex);
+    glDeleteShader(fragment);
+
+    entry->program = program;
+    entry->m = m;
+    entry->v = v;
+    entry->p = p;
+
+    g_free(vertex_shader);
+    g_free(fragment_shader);
+
+    return true;
+}
+