From: John Tsiombikas <nuclear@member.fsf.org>
Date: Thu, 13 Oct 2022 23:33:59 +0000 (+0300)
Subject: foo
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=voxscape;a=commitdiff_plain;h=7efa828ba87fe6c90b8c55019f4789066d2e4af3

foo
---

diff --git a/src/voxscape.c b/src/voxscape.c
index b9a18c3..df34f20 100644
--- a/src/voxscape.c
+++ b/src/voxscape.c
@@ -14,6 +14,7 @@ struct voxscape {
 	int xsz, ysz;
 	unsigned char *height;
 	uint32_t *color;
+	int xshift, xmask, ymask;
 
 	/* framebuffer */
 	uint32_t *fb;
@@ -22,11 +23,13 @@ struct voxscape {
 
 	/* 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;
 
 	unsigned int valid;
 };
@@ -52,6 +55,17 @@ 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->proj_dist = 2;	/* TODO */
+
 	return vox;
 }
 
@@ -124,13 +138,11 @@ void vox_view(struct voxscape *vox, int32_t x, int32_t y, int32_t angle)
 	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 +154,7 @@ void vox_proj(struct voxscape *vox, int fov, int znear, int zfar)
 		return;
 	}
 
-	valid &= ~SLICELEN;
+	vox->valid &= ~SLICELEN;
 }
 
 /* algorithm:
@@ -165,14 +177,17 @@ 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 */
 		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) * 2.0f * 65536.0f);
 		}
 		vox->valid |= SLICELEN;
 	}
@@ -180,9 +195,33 @@ void vox_begin(struct voxscape *vox)
 
 void vox_render_slice(struct voxscape *vox, int n)
 {
-	int32_t len;
+	int i, j, tx, ty, hval, colstart, colheight;
+	int32_t x, y, len, xstep;
+	uint32_t color;
+	uint32_t *fbptr;
 
 	len = vox->slicelen[n];
+	xstep = len / vox->fbwidth;
 
-	/* TODO cont. */
+	x = vox->x - xstep * (vox->fbwidth >> 1);
+	y = vox->y + (vox->znear << 16);
+	for(i=0; i<vox->fbwidth; i++) {
+		tx = (x >> 16) & vox->xmask;
+		ty = (y >> 16) & vox->ymask;
+
+		hval = (vox->height[(ty << vox->xshift) + tx] - vox->vheight) * vox->proj_dist / y;
+		if(hval > vox->coltop[i]) {
+			color = vox->color[(ty << vox->xshift) + tx];
+			colstart = vox->fbheight - 1 - hval;
+			colheight = hval - vox->coltop[i];
+			fbptr = vox->fb + colstart * vox->fbwidth + i;
+
+			for(j=0; j<colheight; j++) {
+				*fbptr = color;
+				fbptr += vox->fbwidth;
+			}
+		}
+
+		x += xstep;
+	}
 }