X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fvoxscape.c;h=54c0b10b3c15ebb4a736dfff0d185fa0ce0d7a08;hb=e10cd82c8f0b2a2140aa6a4792ed56329932271f;hp=b9a18c3eecdda8b36363a70fea637023baa60e3d;hpb=59682b78987c148f793a6d7d7c60280048ca986c;p=voxscape

diff --git a/src/voxscape.c b/src/voxscape.c
index b9a18c3..54c0b10 100644
--- a/src/voxscape.c
+++ b/src/voxscape.c
@@ -3,8 +3,17 @@
 #include <string.h>
 #include <stdint.h>
 #include <math.h>
+#include <assert.h>
 #include <imago2.h>
 #include "voxscape.h"
+#include "lut.h"
+
+#define XLERP(a, b, t, fp) \
+	((((a) << (fp)) + ((b) - (a)) * (t)) >> fp)
+
+static uint32_t lerp_rgb(int r0, int g0, int b0, int r1, int g1, int b1, int32_t t);
+static uint32_t lerp_color(uint32_t ca, uint32_t cb, int32_t t);
+static uint32_t lerp_pcol_rgb(uint32_t pcol, int r, int g, int b, int32_t t);
 
 enum {
 	SLICELEN	= 1
@@ -14,19 +23,28 @@ struct voxscape {
 	int xsz, ysz;
 	unsigned char *height;
 	uint32_t *color;
+	int xshift, xmask, ymask;
+
+	int hfilt, cfilt;
 
 	/* framebuffer */
 	uint32_t *fb;
 	int fbwidth, fbheight;
 	int *coltop;
+	int horizon;
 
 	/* view */
 	int32_t x, y, angle;
+	int vheight;
 
 	/* projection */
 	int fov, znear, zfar;
 	int nslices;
-	int32_t *slicelen;	/* 24.8 */
+	int32_t *slicelen;
+	int proj_dist;
+
+	int zfog;	/* fog start Z (0: no fog) */
+	int fogcolor[3];
 
 	unsigned int valid;
 };
@@ -52,6 +70,18 @@ struct voxscape *vox_create(int xsz, int ysz)
 	vox->xsz = xsz;
 	vox->ysz = ysz;
 
+	vox->xmask = vox->xsz - 1;
+	vox->ymask = vox->ysz - 1;
+
+	vox->xshift = -1;
+	while(xsz) {
+		xsz >>= 1;
+		vox->xshift++;
+	}
+
+	vox->vheight = 80;
+	vox->proj_dist = 4;	/* TODO */
+
 	return vox;
 }
 
@@ -59,7 +89,7 @@ struct voxscape *vox_open(const char *hfile, const char *cfile)
 {
 	unsigned char *hpix;
 	uint32_t *cpix;
-	int width, height, cwidth, cheight;
+	int i, width, height, cwidth, cheight;
 	struct voxscape *vox;
 
 	if(!(hpix = img_load_pixels(hfile, &width, &height, IMG_FMT_GREY8))) {
@@ -83,8 +113,14 @@ struct voxscape *vox_open(const char *hfile, const char *cfile)
 		img_free_pixels(cpix);
 		return 0;
 	}
+
 	memcpy(vox->height, hpix, width * height);
-	memcpy(vox->color, cpix, width * height * sizeof *vox->color);
+
+	/* swap r/b and discard alpha while copying */
+	for(i=0; i<width*height; i++) {
+		vox->color[i] = (cpix[i] & 0xff00) | ((cpix[i] & 0xff) << 16) |
+			((cpix[i] & 0xff0000) >> 16);
+	}
 
 	img_free_pixels(hpix);
 	img_free_pixels(cpix);
@@ -103,7 +139,73 @@ void vox_free(struct voxscape *vox)
 	free(vox);
 }
 
-void vox_framebuf(struct voxscape *vox, int xres, int yres, uint32_t *fb)
+void vox_fog(struct voxscape *vox, int zstart, uint32_t color)
+{
+	vox->zfog = zstart;
+
+	vox->fogcolor[2] = color >> 16;
+	vox->fogcolor[1] = (color >> 8) & 0xff;
+	vox->fogcolor[0] = color & 0xff;
+}
+
+#define H(x, y)	\
+	vox->height[((((y) >> 16) & vox->ymask) << vox->xshift) + (((x) >> 16) & vox->xmask)]
+#define C(x, y) \
+	vox->color[((((y) >> 16) & vox->ymask) << vox->xshift) + (((x) >> 16) & vox->xmask)]
+
+
+int vox_height(struct voxscape *vox, int32_t x, int32_t y)
+{
+	int32_t u, v;
+	int h00, h01, h10, h11, h0, h1;
+
+	if(!vox->hfilt) {
+		return H(x, y);
+	}
+
+	h00 = H(x, y);
+	h01 = H(x, y + 0x10000);
+	h10 = H(x + 0x10000, y);
+	h11 = H(x + 0x10000, y + 0x10000);
+
+	u = x & 0xffff;
+	v = y & 0xffff;
+
+	h0 = XLERP(h00, h01, v, 16);
+	h1 = XLERP(h10, h11, v, 16);
+	return XLERP(h0, h1, u, 16);
+}
+
+int vox_color(struct voxscape *vox, int32_t x, int32_t y)
+{
+	int32_t u, v;
+	uint32_t c00, c01, c10, c11, c0, c1;
+
+	if(!vox->cfilt) {
+		return C(x, y);
+	}
+
+	c00 = C(x, y);
+	c01 = C(x, y + 0x10000);
+	c10 = C(x + 0x10000, y);
+	c11 = C(x + 0x10000, y + 0x10000);
+
+	u = x & 0xffff;
+	v = y & 0xffff;
+
+	c0 = lerp_color(c00, c01, v);
+	c1 = lerp_color(c10, c11, v);
+	return lerp_color(c0, c1, u);
+}
+
+
+void vox_filter(struct voxscape *vox, int hfilt, int cfilt)
+{
+	vox->hfilt = hfilt;
+	vox->cfilt = cfilt;
+}
+
+void vox_framebuf(struct voxscape *vox, int xres, int yres, uint32_t *fb, int horizon)
 {
 	if(xres != vox->fbwidth) {
 		free(vox->coltop);
@@ -115,22 +217,25 @@ void vox_framebuf(struct voxscape *vox, int xres, int yres, uint32_t *fb)
 	vox->fb = fb;
 	vox->fbwidth = xres;
 	vox->fbheight = yres;
+	vox->horizon = horizon >= 0 ? horizon : vox->fbheight / 2;
 }
 
-void vox_view(struct voxscape *vox, int32_t x, int32_t y, int32_t angle)
+void vox_view(struct voxscape *vox, int32_t x, int32_t y, int h, int32_t angle)
 {
+	if(h < 0) {
+		h = vox_height(vox, x, y) - h;
+	}
+
 	vox->x = x;
 	vox->y = y;
+	vox->vheight = h;
 	vox->angle = angle;
-	/* TODO precalc stuff */
 
-	valid &= ~SLICELEN;
+	vox->valid &= ~SLICELEN;
 }
 
 void vox_proj(struct voxscape *vox, int fov, int znear, int zfar)
 {
-	int i;
-
 	vox->fov = fov;
 	vox->znear = znear;
 	vox->zfar = zfar;
@@ -142,7 +247,7 @@ void vox_proj(struct voxscape *vox, int fov, int znear, int zfar)
 		return;
 	}
 
-	valid &= ~SLICELEN;
+	vox->valid &= ~SLICELEN;
 }
 
 /* algorithm:
@@ -165,14 +270,12 @@ void vox_begin(struct voxscape *vox)
 {
 	int i;
 
-	for(i=0; i<vox->fbwidth; i++) {
-		vox->coltop[i] = vox->fbheight;
-	}
+	memset(vox->coltop, 0, vox->fbwidth * sizeof *vox->coltop);
 
 	if(!(vox->valid & SLICELEN)) {
-		float theta = (float)vox->angle * M_PI / 360.0f;	/* half angle */
+		float theta = (float)vox->fov * M_PI / 360.0f;	/* half angle */
 		for(i=0; i<vox->nslices; i++) {
-			vox->slicelen[i] = (int32_t)((vox->znear + i) * tan(theta) * 2.0f * 256.0f)
+			vox->slicelen[i] = (int32_t)((vox->znear + i) * tan(theta) * 4.0f * 65536.0f);
 		}
 		vox->valid |= SLICELEN;
 	}
@@ -180,9 +283,128 @@ void vox_begin(struct voxscape *vox)
 
 void vox_render_slice(struct voxscape *vox, int n)
 {
-	int32_t len;
+	int i, j, hval, colstart, colheight, z;
+	int32_t x, y, len, xstep, ystep, fog;
+	uint32_t color;
+	uint32_t *fbptr;
+
+	if(vox->zfog > 0 && n > vox->zfog) {
+		fog = ((n - vox->zfog) << 16) / (vox->zfar - vox->zfog);
+	} else {
+		fog = 0;
+	}
+
+	z = vox->znear + n;
+
+	len = vox->slicelen[n] >> 8;
+	xstep = ((COS(vox->angle) >> 8) * len) / vox->fbwidth;
+	ystep = ((SIN(vox->angle) >> 8) * len) / vox->fbwidth;
+
+	x = vox->x - SIN(vox->angle) * z - xstep * (vox->fbwidth >> 1);
+	y = vox->y + COS(vox->angle) * z - ystep * (vox->fbwidth >> 1);
+	for(i=0; i<vox->fbwidth; i++) {
+		hval = vox_height(vox, x, y) - vox->vheight;
+		hval = hval * 160 / (vox->znear + n) + vox->horizon;
+		if(hval > vox->fbheight) hval = vox->fbheight;
+		if(hval > vox->coltop[i]) {
+			color = vox_color(vox, x, y);
+			colstart = vox->fbheight - hval;
+			colheight = hval - vox->coltop[i];
+			fbptr = vox->fb + colstart * vox->fbwidth + i;
+
+			if(fog > 0) {
+				color = lerp_pcol_rgb(color, vox->fogcolor[0], vox->fogcolor[1], vox->fogcolor[2], fog);
+			}
+
+			for(j=0; j<colheight; j++) {
+				*fbptr = color;
+				fbptr += vox->fbwidth;
+			}
+			vox->coltop[i] = hval;
+		}
 
-	len = vox->slicelen[n];
+		x += xstep;
+		y += ystep;
+	}
+}
 
-	/* TODO cont. */
+void vox_sky_solid(struct voxscape *vox, uint32_t color)
+{
+	int i, j, colheight;
+	uint32_t *fbptr;
+
+	for(i=0; i<vox->fbwidth; i++) {
+		fbptr = vox->fb + i;
+		colheight = vox->fbheight - vox->coltop[i];
+		for(j=0; j<colheight; j++) {
+			*fbptr = color;
+			fbptr += vox->fbwidth;
+		}
+	}
 }
+
+void vox_sky_grad(struct voxscape *vox, uint32_t chor, uint32_t ctop)
+{
+	int i, j, colheight, t;
+	int r0, g0, b0, r1, g1, b1;
+	int d = vox->fbheight - vox->horizon;
+	uint32_t *grad, *fbptr;
+
+	grad = alloca(vox->fbheight * sizeof *grad);
+
+	b0 = ctop >> 16;
+	g0 = (ctop >> 8) & 0xff;
+	r0 = ctop & 0xff;
+	b1 = chor >> 16;
+	g1 = (chor >> 8) & 0xff;
+	r1 = chor & 0xff;
+
+	for(i=0; i<d; i++) {
+		t = (i << 16) / d;
+		grad[i] = lerp_rgb(r0, g0, b0, r1, g1, b1, t);
+	}
+	for(i=d; i<vox->fbheight; i++) {
+		grad[i] = chor;
+	}
+
+	for(i=0; i<vox->fbwidth; i++) {
+		fbptr = vox->fb + i;
+		colheight = vox->fbheight - vox->coltop[i];
+		for(j=0; j<colheight; j++) {
+			*fbptr = grad[j];
+			fbptr += vox->fbwidth;
+		}
+	}
+}
+
+static uint32_t lerp_rgb(int r0, int g0, int b0, int r1, int g1, int b1, int32_t t)
+{
+	int r = XLERP(r0, r1, t, 16);
+	int g = XLERP(g0, g1, t, 16);
+	int b = XLERP(b0, b1, t, 16);
+	return (b << 16) | (g << 8) | r;
+}
+
+static uint32_t lerp_color(uint32_t ca, uint32_t cb, int32_t t)
+{
+	int r0, g0, b0, r1, g1, b1;
+
+	b0 = ca >> 16;
+	g0 = (ca >> 8) & 0xff;
+	r0 = ca & 0xff;
+	b1 = cb >> 16;
+	g1 = (cb >> 8) & 0xff;
+	r1 = cb & 0xff;
+
+	return lerp_rgb(r0, g0, b0, r1, g1, b1, t);
+}
+
+static uint32_t lerp_pcol_rgb(uint32_t pcol, int r, int g, int b, int32_t t)
+{
+	int b0 = pcol >> 16;
+	int g0 = (pcol >> 8) & 0xff;
+	int r0 = pcol & 0xff;
+
+	return lerp_rgb(r0, g0, b0, r, g, b, t);
+}
+