partial zbuffer implementation #2

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

diff --git a/src/3dgfx/3dgfx.c b/src/3dgfx/3dgfx.c
index e199a64..ef569e6 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];
 
@@ -68,6 +70,8 @@ struct g3d_state {
 
        int vport[4];
 
+       uint16_t clear_color, clear_depth;
+
        /* immediate mode */
        int imm_prim;
        int imm_numv, imm_pcount;
@@ -90,7 +94,7 @@ 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 +105,9 @@ int g3d_init(void)
 
 void g3d_destroy(void)
 {
+#ifdef ENABLE_ZBUFFER
+       free(pfill_zbuf);
+#endif
        free(st);
 }
 
@@ -108,6 +115,9 @@ void g3d_reset(void)
 {
        int i;
 
+#ifdef ENABLE_ZBUFFER
+       free(pfill_zbuf);
+#endif
        memset(st, 0, sizeof *st);
 
        st->opt = G3D_CLIP_FRUSTUM;
@@ -124,19 +134,32 @@ void g3d_reset(void)
        g3d_light_ambient(0.1, 0.1, 0.1);
 
        g3d_mtl_diffuse(1, 1, 1);
+
+       st->clear_depth = 65535;
 }
 
 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(height > prev_height) {
+       if(npixels > max_npixels) {
+               free(pfill_zbuf);
+               pfill_zbuf = malloc(npixels * sizeof *pfill_zbuf);
+               max_npixels = npixels;
+       }
+#endif
+
+       if(height > max_height) {
                polyfill_fbheight(height);
+               max_height = height;
        }
 
        st->width = width;
        st->height = height;
-       st->pixels = pixels;
 
        pfill_fb.pixels = pixels;
        pfill_fb.width = width;
@@ -148,7 +171,6 @@ void g3d_framebuffer(int width, int height, void *pixels)
 /* set the framebuffer pointer, without resetting the size */
 void g3d_framebuffer_addr(void *pixels)
 {
-       st->pixels = pixels;
        pfill_fb.pixels = pixels;
 }
 
@@ -160,6 +182,26 @@ void g3d_viewport(int x, int y, int w, int h)
        st->vport[3] = h;
 }
 
+void g3d_clear_color(unsigned char r, unsigned char g, unsigned char b)
+{
+       st->clear_color = PACK_RGB16(r, g, b);
+}
+
+void g3d_clear_depth(uint16_t zval)
+{
+       st->clear_depth = zval;
+}
+
+void g3d_clear(unsigned int mask)
+{
+       if(mask & G3D_COLOR_BUFFER_BIT) {
+               memset16(pfill_fb.pixels, st->clear_color, pfill_fb.width * pfill_fb.height);
+       }
+       if(mask & G3D_DEPTH_BUFFER_BIT) {
+               memset16(pfill_zbuf, st->clear_depth, pfill_fb.width * pfill_fb.height);
+       }
+}
+
 void g3d_enable(unsigned int opt)
 {
        st->opt |= opt;
@@ -525,7 +567,11 @@ void g3d_draw_indexed(int prim, const struct g3d_vertex *varr, int varr_size,
                        if(v[i].w != 0.0f) {
                                v[i].x /= v[i].w;
                                v[i].y /= v[i].w;
-                               /*v[i].z /= v[i].w;*/
+#ifdef ENABLE_ZBUFFER
+                               if(st->opt & G3D_DEPTH_TEST) {
+                                       v[i].z /= v[i].w;
+                               }
+#endif
                        }
 
                        /* viewport transformation */
@@ -535,6 +581,12 @@ void g3d_draw_indexed(int prim, const struct g3d_vertex *varr, int varr_size,
                        /* convert pos to 24.8 fixed point */
                        pv[i].x = cround64(v[i].x * 256.0f);
                        pv[i].y = cround64(v[i].y * 256.0f);
+#ifdef ENABLE_ZBUFFER
+                       if(st->opt & G3D_DEPTH_TEST) {
+                               /* after div/w z is in [-1, 1], remap it to [0, 65535] */
+                               pv[i].z = cround64(v[i].z * 32767.5f + 32767.5f);
+                       }
+#endif
                        /* convert tex coords to 16.16 fixed point */
                        pv[i].u = cround64(v[i].u * 65536.0f);
                        pv[i].v = cround64(v[i].v * 65536.0f);
@@ -563,7 +615,7 @@ void g3d_draw_indexed(int prim, const struct g3d_vertex *varr, int varr_size,
                case 1:
                        if(st->opt & (G3D_ALPHA_BLEND | G3D_ADD_BLEND)) {
                                int r, g, b, inv_alpha;
-                               g3d_pixel *dest = st->pixels + (pv[0].y >> 8) * st->width + (pv[0].x >> 8);
+                               g3d_pixel *dest = pfill_fb.pixels + (pv[0].y >> 8) * st->width + (pv[0].x >> 8);
                                if(st->opt & G3D_ALPHA_BLEND) {
                                        inv_alpha = 255 - pv[0].a;
                                        r = ((int)pv[0].r * pv[0].a + G3D_UNPACK_R(*dest) * inv_alpha) >> 8;
@@ -579,7 +631,7 @@ void g3d_draw_indexed(int prim, const struct g3d_vertex *varr, int varr_size,
                                }
                                *dest++ = G3D_PACK_RGB(r, g, b);
                        } else {
-                               g3d_pixel *dest = st->pixels + (pv[0].y >> 8) * st->width + (pv[0].x >> 8);
+                               g3d_pixel *dest = pfill_fb.pixels + (pv[0].y >> 8) * st->width + (pv[0].x >> 8);
                                *dest = G3D_PACK_RGB(pv[0].r, pv[0].g, pv[0].b);
                        }
                        break;
@@ -601,6 +653,11 @@ void g3d_draw_indexed(int prim, const struct g3d_vertex *varr, int varr_size,
                        } else if(st->opt & G3D_ADD_BLEND) {
                                fill_mode |= POLYFILL_ADD_BIT;
                        }
+#ifdef ENABLE_ZBUFFER
+                       if(st->opt & G3D_DEPTH_TEST) {
+                               fill_mode |= POLYFILL_ZBUF_BIT;
+                       }
+#endif
                        polyfill(fill_mode, pv, vnum);
                }
        }