1 files changed, 144 insertions, 0 deletions
diff --git a/common.c b/common.c
new file mode 100644
index 0000000..25fc56a
--- /dev/null
+++ b/common.c
@@ -0,0 +1,144 @@
+/*
+  Copyright (c) 2016, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include "common.h"
+
+#include <stdio.h>
+
+#include <GL/glew.h>
+
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_opengl.h>
+
+
+char *filename;
+float current_time = 0;
+
+static GLint time_loc;
+static GLint res_loc;
+
+
+static char * readfile(const char *name) {
+	FILE *f = fopen(name, "r");
+	if (!f)
+		return NULL;
+
+	size_t size = 1024;
+	char *buffer = malloc(size+1);
+	size_t count = 0, r;
+
+	do {
+		if (count == size) {
+			size *= 2;
+			buffer = realloc(buffer, size+1);
+		}
+
+		r = fread(buffer+count, 1, size-count, f);
+		count += r;
+	} while (r);
+
+	fclose(f);
+
+	buffer[count] = 0;
+
+	return buffer;
+}
+
+static void printShaderInfoLog(GLuint obj) {
+	GLint length = 0;
+
+	glGetShaderiv(obj, GL_INFO_LOG_LENGTH, &length);
+
+	if(length > 0) {
+		char log[length];
+
+		glGetShaderInfoLog(obj, sizeof(log), NULL, log);
+		fprintf(stderr, "%s\n", log);
+	}
+}
+
+static void printProgramInfoLog(GLuint obj) {
+	GLint length = 0;
+
+	glGetProgramiv(obj, GL_INFO_LOG_LENGTH, &length);
+
+	if(length > 0) {
+		char log[length];
+
+		glGetProgramInfoLog(obj, sizeof(log), NULL, log);
+		fprintf(stderr, "%s\n", log);
+	}
+}
+
+void load(void) {
+	char *shader = readfile(filename);
+	if (!shader) {
+		fprintf(stderr, "Error: unable to read '%s'\n", filename);
+		return;
+	}
+
+	GLuint frag = glCreateShader(GL_FRAGMENT_SHADER);
+	glShaderSource(frag, 1, (const GLchar **)&shader, NULL);
+	glCompileShader(frag);
+	printShaderInfoLog(frag);
+
+	GLuint program = glCreateProgram();
+	glAttachShader(program, frag);
+
+	glLinkProgram(program);
+	printProgramInfoLog(program);
+
+	glBindFragDataLocation(program, 0, "fragColor");
+	time_loc = glGetUniformLocation(program, "time");
+	res_loc = glGetUniformLocation(program, "res");
+
+	extra_load(program);
+
+	glUseProgram(program);
+
+	free(shader);
+	glDeleteShader(frag);
+	glDeleteProgram(program);
+}
+
+void init(void) {
+	glewInit();
+	glDisable(GL_DEPTH_TEST);
+	glColor4f(0, 0, 0, 0);
+}
+
+void render(int width, int height) {
+	glViewport(0, 0, (GLsizei)width, (GLsizei)height);
+
+	glUniform1f(time_loc, current_time);
+	glUniform2f(res_loc, width, height);
+
+	glBegin(GL_QUADS);
+	glVertex2f(-1, -1);
+	glVertex2f(1, -1);
+	glVertex2f(1, 1);
+	glVertex2f(-1, 1);
+	glEnd();
+}