added opengl_animation for the "Tage der offenen Ateliers"

opengl_animation/Makefile

+all:
+	$(CC) -Wall -O3 -std=c99 $(shell sdl-config --cflags) -o warpzone_animation *.c -lm -lGL $(shell sdl-config --libs)

opengl_animation/warpzone_animation.c

+// Using legacy OpenGL to render our animated logo
+// ands
+
+#define _BSD_SOURCE
+#include <unistd.h>
+#include <stdio.h>
+#include <math.h>
+#include <GL/gl.h>
+#include <SDL/SDL.h>
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
+// avoids depending on glext.h for just these two defines
+#ifndef GL_TEXTURE_MAX_ANISOTROPY
+#define GL_TEXTURE_MAX_ANISOTROPY 0x84FE
+#endif
+#ifndef GL_MAX_TEXTURE_MAX_ANISOTROPY
+#define GL_MAX_TEXTURE_MAX_ANISOTROPY 0x84FF
+#endif
+
+// texture enumeration
+#define RADIAL0			0
+#define RADIAL1			1
+#define RADIAL2			2
+#define ARROW			3
+#define EVENTS			4
+#define TEXT			5
+#define TEXTURES_NUM	6
+
+const char *texture_files[] =
+{
+	"radial0.png",
+	"radial1.png",
+	"radial2.png",
+	"arrow.png",
+	"events.png",
+	"text.png"
+};
+
+GLuint textures[TEXTURES_NUM] = { 0 };
+
+static void draw_quad(float size)
+{
+	glBegin(GL_QUADS);
+		glTexCoord2f(0.0f, 0.0f); glVertex2f(-size,  size);
+		glTexCoord2f(1.0f, 0.0f); glVertex2f( size,  size);
+		glTexCoord2f(1.0f, 1.0f); glVertex2f( size, -size);
+		glTexCoord2f(0.0f, 1.0f); glVertex2f(-size, -size);
+	glEnd();
+}
+
+static void draw_logo(double time)
+{
+	// draw radials
+	for (int i = 0; i < 3; i++)
+	{
+		glPushMatrix();
+			glRotatef(20.0f * cos(time * 2.0f), 0.0f, 1.0f, 0.0f);
+			glTranslatef(0.0f, 0.8f, 0.0f);
+			glRotatef(time * 32.0f * (0.5f + (i - 1)) , 0.0f, 0.0f, 1.0f);
+			glBindTexture(GL_TEXTURE_2D, textures[RADIAL0 + i]);
+			draw_quad(1.0f);
+		glPopMatrix();
+	}
+
+	// draw text
+	glPushMatrix();
+		glRotatef(60.0f * sin(time), 0.0f, 1.0f, 0.0f);
+		glTranslatef(0.0f, -0.8f, 0.0f);
+		glBindTexture(GL_TEXTURE_2D, textures[TEXT]);
+		draw_quad(1.0f);
+	glPopMatrix();
+}
+
+static void draw_events(double time)
+{
+	// draw events
+	glPushMatrix();
+		glRotatef(30.0f * sin(time), 0.0f, 1.0f, 0.0f);
+		glBindTexture(GL_TEXTURE_2D, textures[EVENTS]);
+		draw_quad(1.0f);
+	glPopMatrix();
+	
+	// draw arrows
+	glPushMatrix();
+		glTranslatef(0.0f, -1.5f, 0.0f);
+		glRotatef(-50.0f + 20.0f * cos(time * 2.0f), 0.0f, 1.0f, 0.0f);
+		glBindTexture(GL_TEXTURE_2D, textures[ARROW]);
+		draw_quad(0.4f);
+	glPopMatrix();
+	glPushMatrix();
+		glTranslatef(0.0f, 1.5f, 0.0f);
+		glRotatef(50.0f + 20.0f * cos(time * 2.5f), 0.0f, 1.0f, 0.0f);
+		glBindTexture(GL_TEXTURE_2D, textures[ARROW]);
+		draw_quad(0.4f);
+	glPopMatrix();
+}
+
+#define SWITCH_INTERVAL 10.0 // seconds
+
+int main(int argc, char **argv)
+{
+	// initialize window + opengl context
+	SDL_Init(SDL_INIT_VIDEO);
+	const SDL_VideoInfo* info = SDL_GetVideoInfo();
+	SDL_SetVideoMode(info->current_w, info->current_h, 0, SDL_OPENGL | SDL_FULLSCREEN);
+	SDL_ShowCursor(SDL_DISABLE);
+	
+	// initial opengl state
+	glEnable(GL_TEXTURE_2D);
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_ONE, GL_ONE);
+	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+	
+	// camera projection setup
+	glMatrixMode(GL_PROJECTION);
+	const double fov = 50.0, aspect = info->current_w / (double)info->current_h, near = 0.1, far = 1000.0;
+	const double half_height = tan(fov / 360.0 * 3.14159) * near;
+	const double half_width = half_height * aspect;
+	glFrustum(-half_width, half_width, -half_height, half_height, near, far);
+	glMatrixMode(GL_MODELVIEW);
+
+	// load textures
+	GLfloat max_anisotropy;
+	glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY, &max_anisotropy);
+	
+	glGenTextures(TEXTURES_NUM, textures);
+	for (int i = 0; i < TEXTURES_NUM; i++)
+	{
+		int x, y, n;
+		unsigned char *data = stbi_load(texture_files[i], &x, &y, &n, 3);
+		if (data == NULL)
+		{
+			fprintf(stderr, "Could not load file: %s", texture_files[i]);
+			exit(-1);
+		}
+		
+		glBindTexture(GL_TEXTURE_2D, textures[i]);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY, max_anisotropy);
+		glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, x, y, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+		
+		stbi_image_free(data);
+	}
+	
+	// rendering loop
+	SDL_Event event;
+	do
+	{
+		// get current time
+		double time = SDL_GetTicks() / 1000.0;
+		
+		// clear output buffer
+		glClear(GL_COLOR_BUFFER_BIT /*| GL_DEPTH_BUFFER_BIT*/);
+		
+		glLoadIdentity();
+		glTranslatef(0.0f, 0.0f, -3.0f); // camera positioning
+		glRotatef(-90.0f, 0.0f, 0.0f, 1.0f); // beamer rotation
+		glRotatef(180.0f, 0.0f, 1.0f, 0.0f); // horizontal "flip"
+		
+		if ((int)(time/SWITCH_INTERVAL) & 1)
+			draw_logo(time);
+		else
+			draw_events(time);
+		
+		// flush buffer and wait for next frame
+		SDL_GL_SwapBuffers();
+		usleep(16000); // save cpu time (~60FPS)
+		SDL_PollEvent(&event);
+	} while(event.type != SDL_KEYDOWN);
+	
+	// clean up
+	glDeleteTextures(TEXTURES_NUM, textures);
+	SDL_Quit();
+}