shithub: tinygl

ref: 3aaf17bc54e0ab5bc103036d016a76283c371517
dir: /src/specbuf.c/

#include "msghandling.h"
#include "zgl.h"
#include <math.h>
#include <stdlib.h>

static void calc_buf(GLSpecBuf* buf, const GLfloat shininess) {
	GLint i;
	GLfloat val, inc;
	val = 0.0f;
	inc = 1.0f / SPECULAR_BUFFER_SIZE;
	for (i = 0; i <= SPECULAR_BUFFER_SIZE; i++) {
		buf->buf[i] = pow(val, shininess);
		val += inc;
	}
}

GLSpecBuf* specbuf_get_buffer(GLContext* c, const GLint shininess_i, const GLfloat shininess) {
	GLSpecBuf *found, *oldest;
	found = oldest = c->specbuf_first;
	while (found && found->shininess_i != shininess_i) {
		if (found->last_used < oldest->last_used) {
			oldest = found;
		}
		found = found->next;
	}
	if (found) { /* hey, found one! */
		found->last_used = c->specbuf_used_counter++;
		return found;
	}
	if (oldest == NULL || c->specbuf_num_buffers < MAX_SPECULAR_BUFFERS) {
		/* create new buffer */
		GLSpecBuf* buf = gl_malloc(sizeof(GLSpecBuf));
		if (!buf)
			gl_fatal_error("could not allocate specular buffer");
		c->specbuf_num_buffers++;
		buf->next = c->specbuf_first;
		c->specbuf_first = buf;
		buf->last_used = c->specbuf_used_counter++;
		buf->shininess_i = shininess_i;
		calc_buf(buf, shininess);
		return buf;
	}
	/* overwrite the lru buffer */
	/*tgl_trace("overwriting spec buffer :(\n");*/
	oldest->shininess_i = shininess_i;
	oldest->last_used = c->specbuf_used_counter++;
	calc_buf(oldest, shininess);
	return oldest;
}