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vdp1/cube2: add perspective division

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This commit is contained in:
Zack Buhman 2024-09-12 10:49:54 -05:00
parent 3bb4740030
commit b80cac2743
1 changed files with 19 additions and 24 deletions
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43
vdp1/cube2.cpp
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@ -45,7 +45,8 @@ consteval vec3 normal(int32_t ix)
const uint32_t * face = faces[ix];
vec3 a = vertices[face[1]] - vertices[face[0]];
vec3 b = vertices[face[3]] - vertices[face[0]];
return vertices[face[0]] + cross(a, b);
//return vertices[face[0]] + cross(a, b);
return cross(a, b);
}
static constexpr vec3 normals[6] = {
@ -121,44 +122,38 @@ render()
const uint32_t * face = faces[i];
const vec3& origin = transform * vertices[face[0]];
const vec3& normal = (transform * normals[i]);
const vec3& origin_p = project_vertex(origin);
const vec3& normal_p = project_vertex(normal);
const vec3 camera = {2.0/3.0, 0.5, 100};
fp16_16 cull = dot((origin - camera), normal - origin);
// rotation
const vec3& origin0 = transform * vertices[face[0]];
// translation
const vec3& origin{origin0.x, origin0.y + fp16_16(1), origin0.z + fp16_16(2)};
if ((cull.value >> 16) < 0) {
const vec3& normal = transform * normals[i];
const vec3 camera = {0, 0, 0};
fp16_16 cull = dot((camera - origin), normal);
if (cull.value > 0) {
vdp1.vram.cmd[ix].CTRL = CTRL__JP__JUMP_NEXT | CTRL__COMM__POLYGON;
vdp1.vram.cmd[ix].LINK = 0;
vdp1.vram.cmd[ix].PMOD = PMOD__ECD | PMOD__SPD;
vdp1.vram.cmd[ix].COLR = COLR__RGB | colors[i];
// `origin` above is p==0 below; the `origin` calculation could
// be reused, though it would hurt readability slightly
for (int p = 0; p < 4; p++) {
const vec3& v0 = vertices[face[p]];
// rotation
const vec3 v1 = transform * v0;
// translation
const vec3 v2{v1.x, v1.y + fp16_16(1), v1.z + fp16_16(2)};
const vec3& v2 = project_vertex(v1);
const vec3 v3 = project_vertex(v2 / v2.z);
vdp1.vram.cmd[ix].point[p].X = static_cast<int>(v2.x);
vdp1.vram.cmd[ix].point[p].Y = static_cast<int>(v2.y);
vdp1.vram.cmd[ix].point[p].X = static_cast<int>(v3.x);
vdp1.vram.cmd[ix].point[p].Y = static_cast<int>(v3.y);
}
ix++;
/*
vdp1.vram.cmd[ix].CTRL = CTRL__JP__JUMP_NEXT | CTRL__COMM__LINE;
vdp1.vram.cmd[ix].LINK = 0;
vdp1.vram.cmd[ix].PMOD = PMOD__ECD | PMOD__SPD;
vdp1.vram.cmd[ix].COLR = COLR__RGB | colors[i];
vdp1.vram.cmd[ix].point[0].X = static_cast<int>(origin_p.x);
vdp1.vram.cmd[ix].point[0].Y = static_cast<int>(origin_p.y);
vdp1.vram.cmd[ix].point[1].X = static_cast<int>(normal_p.x);
vdp1.vram.cmd[ix].point[1].Y = static_cast<int>(normal_p.y);
ix++;
*/
}
}