aabb2 cast_aabb(game* g, aabb2 self, vec2 delta, int* clipped) {
aabb2 bounds(expand_toward(self, delta));
int x0 = fast_floor(bounds.min.x);
int y0 = fast_floor(bounds.min.y);
int x1 = fast_floor(bounds.max.x);
int y1 = fast_floor(bounds.max.y);
vec2 clipped_delta = delta;
for(int x = x0; x <= x1; x++) {
for(int y = y0; y <= y1; y++) {
if (g->get_tile(x, y) != TT_EMPTY) {
clipped_delta.x = clip_x(aabb2(vec2((float)x, (float)y), vec2((float)(x + 1), (float)(y + 1))), self, clipped_delta.x);
}
}
}
self.min.x += clipped_delta.x;
self.max.x += clipped_delta.x;
for(int x = x0; x <= x1; x++) {
for(int y = y0; y <= y1; y++) {
if (g->get_tile(x, y) != TT_EMPTY) {
clipped_delta.y = clip_y(aabb2(vec2((float)x, (float)y), vec2((float)(x + 1), (float)(y + 1))), self, clipped_delta.y);
}
}
}
self.min.y += clipped_delta.y;
self.max.y += clipped_delta.y;
if (clipped) {
*clipped = 0;
if (delta.x != clipped_delta.x) *clipped |= (delta.x > 0.0f) ? CLIPPED_XP : CLIPPED_XN;
if (delta.y != clipped_delta.y) *clipped |= (delta.y > 0.0f) ? CLIPPED_YP : CLIPPED_YN;
}
return self;
}
bool clip_cg_line
(
sk_cg_geometry *source,
int x_min,
int y_min,
int x_max,
int y_max
)
{
if (!source)
{
return false;
}
UINT_8 code_a = cohen_code_cg_point(&source->geometry.line.a,
x_min,
y_min,
x_max,
y_max);
UINT_8 code_b = cohen_code_cg_point(&source->geometry.line.b,
x_min,
y_min,
x_max,
y_max);
if (code_a & code_b)
{
// If line segments are completely outside the window,
// c_0 & c_1 != 0
return false;
}
UINT_8 code = code_a ^ code_b;
UINT_64 x_c = 0;
UINT_64 y_c = 0;
while (code)
{
if (code & 0x1)
{
clip_x(&source->geometry.line.a,
&source->geometry.line.b,
code_a & 0x1 ? &source->geometry.line.a
: &source->geometry.line.b,
x_min);
}
else if (code & 0x2)
{
clip_x(&source->geometry.line.a,
&source->geometry.line.b,
code_a & 0x2 ? &source->geometry.line.a
: &source->geometry.line.b,
x_max);
}
else if (code & 0x4)
{
clip_y(&source->geometry.line.a,
&source->geometry.line.b,
code_a & 0x4 ? &source->geometry.line.a
: &source->geometry.line.b,
y_min);
}
else if (code & 0x8)
{
clip_y(&source->geometry.line.a,
&source->geometry.line.b,
code_a & 0x8 ? &source->geometry.line.a
: &source->geometry.line.b,
y_max);
}
code_a = cohen_code_cg_point(&source->geometry.line.a, x_min, y_min, x_max, y_max);
code_b = cohen_code_cg_point(&source->geometry.line.b, x_min, y_min, x_max, y_max);
code = code_a ^ code_b;
continue;
}
return !(code_a & code_b);
}
