WIP: utils.c for factoring opengl tedious tasks, switch to OpenGL 3.3HEADmaster

For now, it display nothing, shaders changed without updating client code.

5 files changed, 148 insertions, 67 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index d9f8a72..b7acbeb 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,5 +1,5 @@
 bin_PROGRAMS = demoscene-eo
-demoscene_eo_SOURCES = demoscene-eo.c scene00.c scene01.c scene02.c
+demoscene_eo_SOURCES = demoscene-eo.c utils.c scene00.c scene01.c scene02.c
 
 server-local: demoscene-eo
 	xterm -e $(SHELL) -c "sleep 1; nc -v localhost 51914; exec $(SHELL)" &
diff --git a/src/demoscene-eo.c b/src/demoscene-eo.c
index ed6fe1b..1c532be 100644
--- a/src/demoscene-eo.c
+++ b/src/demoscene-eo.c
@@ -159,7 +159,7 @@ int parent() {
 					case 2: res = scene02_init_caca(&shm->ge, &shm->s02e); break;
 				}
 				// If scene init fail, skip to the next one
-				if (res) SCENE_NEXT; else lastscene = shm->scene;
+				if (res) { printf("scene%02i_init_caca() returned %i\n", shm->scene, res); SCENE_NEXT; } else lastscene = shm->scene;
 			}
 			shm->ge.sdl_ticks = SDL_GetTicks(); // This value wraps if the program runs for more than ~49 days
 
@@ -288,7 +288,7 @@ int worker_sdl() {
 					case 2: res = scene02_init_sdl(&shm->ge, &shm->s02e); break;
 				}
 				// If scene init fail, skip to the next one
-				if (res) SCENE_NEXT; else lastscene = shm->scene;
+				if (res) { printf("scene%02i_init_sdl() returned %i\n", shm->scene, res); SCENE_NEXT; } else lastscene = shm->scene;
 			}
 			// Compute current scene frame (sdl part)
 			switch(shm->scene) {
@@ -413,7 +413,7 @@ int worker_gl() {
 					case 2: res = scene02_init_gl(&shm->ge, &shm->s02e); break;
 				}
 				// If scene init fail, skip to the next one
-				if (res) SCENE_NEXT; else lastscene = shm->scene;
+				if (res) { printf("scene%02i_init_gl() returned %i\n", shm->scene, res); SCENE_NEXT; } else lastscene = shm->scene;
 			}
 
 			// Compute current scene frame (gl part)
diff --git a/src/scene01.c b/src/scene01.c
index a93aa3d..05457bc 100644
--- a/src/scene01.c
+++ b/src/scene01.c
@@ -18,55 +18,9 @@
  *  along with demoscene-eo.  If not, see <http://www.gnu.org/licenses/>
  */
 #include "scene01.h"
+#include "utils.h"
 
 // Mostly inspired by CC0 https://gist.github.com/koute/7391344
-typedef float t_mat4x4[16];
-
-static inline void mat4x4_ortho(t_mat4x4 out, float left, float right, float bottom, float top, float znear, float zfar)
-{
-	#define T(a, b) (a * 4 + b)
-
-	out[T(0,0)] = 2.0f / (right - left);
-	out[T(0,1)] = 0.0f;
-	out[T(0,2)] = 0.0f;
-	out[T(0,3)] = 0.0f;
-
-	out[T(1,1)] = 2.0f / (top - bottom);
-	out[T(1,0)] = 0.0f;
-	out[T(1,2)] = 0.0f;
-	out[T(1,3)] = 0.0f;
-
-	out[T(2,2)] = -2.0f / (zfar - znear);
-	out[T(2,0)] = 0.0f;
-	out[T(2,1)] = 0.0f;
-	out[T(2,3)] = 0.0f;
-
-	out[T(3,0)] = -(right + left) / (right - left);
-	out[T(3,1)] = -(top + bottom) / (top - bottom);
-	out[T(3,2)] = -(zfar + znear) / (zfar - znear);
-	out[T(3,3)] = 1.0f;
-
-	#undef T
-}
-
-static const char * vertex_shader =
-	"#version 130\n"
-	"in vec2 i_position;\n"
-	"in vec4 i_color;\n"
-	"out vec4 v_color;\n"
-	"uniform mat4 u_projection_matrix;\n"
-	"void main() {\n"
-	"	v_color = i_color;\n"
-	"	gl_Position = u_projection_matrix * vec4(i_position, 0.0, 1.0);\n"
-	"}\n";
-
-static const char * fragment_shader =
-	"#version 130\n"
-	"in vec4 v_color;\n"
-	"out vec4 o_color;\n"
-	"void main() {\n"
-	"	o_color = v_color;\n"
-	"}\n";
 
 typedef enum t_attrib_id
 {
@@ -81,29 +35,29 @@ int scene01_init_gl(graphical_env_t *ge, scene01_env_t *se) {
 
 	TRACE("call");
 	vs = glCreateShader(GL_VERTEX_SHADER);
-	fs = glCreateShader(GL_FRAGMENT_SHADER);
+	status = gl_compile_shader_from_file(vs, "res/scene01_vs_basic.glsl"); if (status) return 40+status;
 
-	int length = strlen(vertex_shader);
-	glShaderSource(vs, 1, (const GLchar **)&vertex_shader, &length);
-	glCompileShader(vs);
-
-	glGetShaderiv(vs, GL_COMPILE_STATUS, &status);
-	if(status == GL_FALSE) return 40;
-
-	length = strlen(fragment_shader);
-	glShaderSource(fs, 1, (const GLchar **)&fragment_shader, &length);
-	glCompileShader(fs);
-
-	glGetShaderiv(fs, GL_COMPILE_STATUS, &status);
-	if(status == GL_FALSE) return 41;
+	fs = glCreateShader(GL_FRAGMENT_SHADER);
+	status = gl_compile_shader_from_file(fs, "res/scene01_fs_colorfultest.glsl"); if (status) return 50+status;
 
 	program = glCreateProgram();
 	glAttachShader(program, vs);
 	glAttachShader(program, fs);
-
 	glBindAttribLocation(program, attrib_position, "i_position");
 	glBindAttribLocation(program, attrib_color, "i_color");
+
 	glLinkProgram(program);
+	glGetProgramiv(program, GL_LINK_STATUS, &status);
+
+	glDetachShader(program, vs);
+	glDetachShader(program, fs);
+	glDeleteShader(vs);
+	glDeleteShader(fs);
+
+	if(status == GL_FALSE) {
+		gl_trace_shader_or_program_log(program);
+		return 60;
+	}
 
 	glUseProgram(program);
 
@@ -171,7 +125,7 @@ int scene01_init_gl(graphical_env_t *ge, scene01_env_t *se) {
 	glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
 
 	t_mat4x4 projection_matrix;
-	mat4x4_ortho(projection_matrix, 0.0f, (float)FBUF_W, (float)FBUF_H, 0.0f, 0.0f, 100.0f);
+	gl_mat4x4_ortho(projection_matrix, 0.0f, (float)FBUF_W, (float)FBUF_H, 0.0f, 0.0f, 100.0f);
 	glUniformMatrix4fv(glGetUniformLocation(program, "u_projection_matrix"), 1, GL_FALSE, projection_matrix);
 
 
diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..a3c878e
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,114 @@
+#include "utils.h"
+
+// Mostly inspired by CC0 https://gist.github.com/koute/7391344
+void gl_mat4x4_ortho(t_mat4x4 out, float left, float right, float bottom, float top, float znear, float zfar)
+{
+	#define T(a, b) (a * 4 + b)
+
+	out[T(0,0)] = 2.0f / (right - left);
+	out[T(0,1)] = 0.0f;
+	out[T(0,2)] = 0.0f;
+	out[T(0,3)] = 0.0f;
+
+	out[T(1,1)] = 2.0f / (top - bottom);
+	out[T(1,0)] = 0.0f;
+	out[T(1,2)] = 0.0f;
+	out[T(1,3)] = 0.0f;
+
+	out[T(2,2)] = -2.0f / (zfar - znear);
+	out[T(2,0)] = 0.0f;
+	out[T(2,1)] = 0.0f;
+	out[T(2,3)] = 0.0f;
+
+	out[T(3,0)] = -(right + left) / (right - left);
+	out[T(3,1)] = -(top + bottom) / (top - bottom);
+	out[T(3,2)] = -(zfar + znear) / (zfar - znear);
+	out[T(3,3)] = 1.0f;
+
+	#undef T
+}
+
+// Mostly inspired from https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_02
+
+// Store all the file's contents in memory, useful to pass shaders source code to OpenGL.
+const GLchar* gl_shaderfile_read(const char* path, Sint64 *out_fsize) {
+	GLchar *buf, *cursor;
+	SDL_RWops *rw;
+	Sint64 fsize;
+	size_t read;
+
+	rw = SDL_RWFromFile(path, "rb"); if (rw == NULL) return NULL;
+	fsize = SDL_RWsize(rw); if (fsize == -1) return NULL;
+	buf = malloc(fsize+1); if (buf == NULL) return NULL;
+
+	cursor = buf;
+	read = 0;
+	do {
+		cursor += read;
+		// Read at most to the end of buf
+		read = SDL_RWread(rw, cursor, 1, (fsize - (cursor-buf)));
+	 } while ( read > 0 );
+	*cursor = '\0'; // Where the +1 is used from malloc() call
+
+	SDL_RWclose(rw);
+
+	// Check if we have read the whole thing
+	if ( (cursor-buf) != fsize) {
+		free(buf);
+		return NULL;
+	}
+
+	if (out_fsize != NULL) *out_fsize = fsize;
+	return buf;
+}
+
+/**
+ * Display compilation errors from the OpenGL shader compiler
+ */
+void gl_trace_shader_or_program_log(GLuint object) {
+	GLint log_length = 0;
+	char *log;
+
+	if (glIsShader(object)) {
+		glGetShaderiv(object, GL_INFO_LOG_LENGTH, &log_length);
+	} else if (glIsProgram(object)) {
+		glGetProgramiv(object, GL_INFO_LOG_LENGTH, &log_length);
+	} else {
+		TRACE("not a shader or a program");
+		return;
+	}
+
+	log = (char*)malloc(log_length);
+	if ( log == NULL ) {
+		TRACE("malloc failed");
+		return;
+	}
+
+	if (glIsShader(object))
+		glGetShaderInfoLog(object, log_length, NULL, log);
+	else if (glIsProgram(object))
+		glGetProgramInfoLog(object, log_length, NULL, log);
+
+	TRACE(log);
+	free(log);
+}
+
+GLint gl_compile_shader_from_file(GLuint shader, const char* path) {
+	Sint64 fsize;
+	GLint gl_fsize, status;
+
+	const GLchar *source = gl_shaderfile_read(path, &fsize);
+	if (source == NULL) return 1;
+
+	gl_fsize = (GLint) fsize;
+	glShaderSource(shader, 1, &source, &gl_fsize);
+	glCompileShader(shader);
+	glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+	if(status == GL_FALSE) {
+		gl_trace_shader_or_program_log(shader);
+		return 2;
+	}
+
+	return 0;
+}
+
diff --git a/src/utils.h b/src/utils.h
new file mode 100644
index 0000000..586e152
--- /dev/null
+++ b/src/utils.h
@@ -0,0 +1,13 @@
+#ifndef UTILS_H_INCLUDED
+#define UTILS_H_INCLUDED
+
+#include "main.h"
+
+typedef float t_mat4x4[16];
+void gl_mat4x4_ortho(t_mat4x4 out, float left, float right, float bottom, float top, float znear, float zfar);
+
+const GLchar* gl_shaderfile_read(const char* path, Sint64 *out_fsize);
+void gl_trace_shader_or_program_log(GLuint object);
+GLint gl_compile_shader_from_file(GLuint shader, const char* path);
+
+#endif