zbuffer partial implementation

[dosdemo] / src / 3dgfx / 3dgfx.c

diff --git a/src/3dgfx/3dgfx.c b/src/3dgfx/3dgfx.c
index e199a64..16024f8 100644 (file)
--- a/src/3dgfx/3dgfx.c
+++ b/src/3dgfx/3dgfx.c
@@ -17,6 +17,8 @@
 #include "demo.h"
 #include "util.h"
 
+#define ENABLE_ZBUFFER
+
 #define STACK_SIZE     8
 typedef float g3d_matrix[16];
 
@@ -90,7 +92,7 @@ static const float idmat[] = {
 
 int g3d_init(void)
 {
-       if(!(st = malloc(sizeof *st))) {
+       if(!(st = calloc(1, sizeof *st))) {
                fprintf(stderr, "failed to allocate G3D context\n");
                return -1;
        }
@@ -101,6 +103,9 @@ int g3d_init(void)
 
 void g3d_destroy(void)
 {
+#ifdef ENABLE_ZBUFFER
+       free(pfill_zbuf);
+#endif
        free(st);
 }
 
@@ -108,6 +113,9 @@ void g3d_reset(void)
 {
        int i;
 
+#ifdef ENABLE_ZBUFFER
+       free(pfill_zbuf);
+#endif
        memset(st, 0, sizeof *st);
 
        st->opt = G3D_CLIP_FRUSTUM;
@@ -128,10 +136,22 @@ void g3d_reset(void)
 
 void g3d_framebuffer(int width, int height, void *pixels)
 {
-       static int prev_height;
+       static int max_height;
+
+#ifdef ENABLE_ZBUFFER
+       static int max_npixels;
+       int npixels = width * height;
+
+       if(npixels > max_npixels) {
+               free(pfill_zbuf);
+               pfill_zbuf = malloc(npixels * sizeof *pfill_zbuf);
+               max_npixels = npixels;
+       }
+#endif
 
-       if(height > prev_height) {
+       if(height > max_height) {
                polyfill_fbheight(height);
+               max_height = height;
        }
 
        st->width = width;