Text rendering / Proper projection

Author Mitja Felicijan <mitja.felicijan@gmail.com> 2026-05-11 16:14:51 +0200
Committer Mitja Felicijan <mitja.felicijan@gmail.com> 2026-05-11 17:08:26 +0200
Commit 2c04d3a962ec4019f17ba9e570b309e69456a689 (patch)
-rw-r--r-- main.c 44
1 files changed, 40 insertions, 4 deletions
diff --git a/main.c b/main.c
...
12 
    #include <GL/glut.h>
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    #include <GL/glut.h>
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#endif
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#endif
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typedef struct {
 
  
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	float x, y, z;
 
  
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} Vec2;
 
  
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typedef struct {
 
  
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	float x, y, z;
 
  
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} Vec3;
 
  
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typedef struct {
 
  
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	float x, y, z, w;
 
  
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} Vec4;
 
  
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#define COLOR_RED     (Vec3){ .x = 1.0f, .y = 0.0f, .z = 0.0f }
 
  
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#define COLOR_GREEN   (Vec3){ .x = 0.0f, .y = 1.0f, .z = 0.0f }
 
  
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#define COLOR_BLUE    (Vec3){ .x = 0.0f, .y = 0.0f, .z = 1.0f }
 
  
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#define COLOR_WHITE   (Vec3){ .x = 1.0f, .y = 1.0f, .z = 1.0f }
 
  
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#define COLOR_BLACK   (Vec3){ .x = 0.0f, .y = 0.0f, .z = 0.0f }
 
  
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#define COLOR_YELLOW  (Vec3){ .x = 1.0f, .y = 1.0f, .z = 0.0f }
 
  
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#define COLOR_CYAN    (Vec3){ .x = 0.0f, .y = 1.0f, .z = 1.0f }
 
  
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#define COLOR_MAGENTA (Vec3){ .x = 1.0f, .y = 0.0f, .z = 1.0f }
 
  
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#define COLOR_ORANGE  (Vec3){ .x = 1.0f, .y = 0.5f, .z = 0.0f }
 
  
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#define COLOR_PURPLE  (Vec3){ .x = 0.5f, .y = 0.0f, .z = 0.5f }
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typedef struct {
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typedef struct {
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	int target_fps;
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	int target_fps;
...
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	free(data);
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	free(data);
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}
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}
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void render_text(float x, float y, void* font, const char* string) {
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void draw_text(float x, float y, void* font, const char* string, Vec3 color) {
 
  
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	glColor3f(color.x, color.y, color.z);
 
  
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	glMatrixMode(GL_PROJECTION);
 
  
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	glPushMatrix();
 
  
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	glLoadIdentity();
 
  
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	glOrtho(0, 1, 0, 1, -1, 1);
 
  
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	glMatrixMode(GL_MODELVIEW);
 
  
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	glPushMatrix();
 
  
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	glLoadIdentity();
 
  
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	glRasterPos2f(x, y);
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	glRasterPos2f(x, y);
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	for (const char* c = string; *c != '\0'; c++) {
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	for (const char* c = string; *c != '\0'; c++) {
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		glutBitmapCharacter(font, *c);
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		glutBitmapCharacter(font, *c);
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	}
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	}
 
  
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	glPopMatrix();
 
  
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	glMatrixMode(GL_PROJECTION);
 
  
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	glPopMatrix();
 
  
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	glMatrixMode(GL_MODELVIEW);
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}
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}
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void draw_cube(void) {
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void draw_cube(void) {
...
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	glPopMatrix();
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	glPopMatrix();
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	// Render UI Text
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	// Render UI Text
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	glLoadIdentity();
 
  
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	glColor3f(0.0, 1.0, 0.0);
 
  
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	char fps_text[32];
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	char fps_text[32];
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	snprintf(fps_text, sizeof fps_text, "FPS: %d", game.target_fps);
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	snprintf(fps_text, sizeof fps_text, "FPS: %d", game.target_fps);
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	render_text(0.05f, 0.93f, GLUT_BITMAP_HELVETICA_18, fps_text);
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	draw_text(0.01f, 0.95f, GLUT_BITMAP_HELVETICA_18, fps_text, COLOR_GREEN);
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	glutSwapBuffers();
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	glutSwapBuffers();
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}
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}
...