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port over dual frustum clipping from interstice

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This commit is contained in:
Shpuld Shpuldson 2023-09-16 16:00:48 +03:00
parent 2712c3fdfd
commit c782d49c77
3 changed files with 108 additions and 7 deletions
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95
source/psp/clipping.cpp
View file

@ -76,6 +76,27 @@ namespace quake
static ScePspFMatrix4 projection_view_matrix __attribute__((aligned(16)));
static frustum_t projection_view_frustum __attribute__((aligned(16)));
static frustum_t clipping_frustum __attribute__((aligned(16)));
/*
shpuld's magical clipping adventures:
wide frustum explained, PSP hardware cull happens when any vert goes past the 0-4095 virtual coordinate space (VCS)
the viewport is centered in the middle of the VCS, so verts that go enough pixels past any of the screen edges to reach
the edge of the VCS get culled completely. this is why we need some kind of frustum clipping. however clipping to view
frustum is very wasteful, as most polys clipped to it would not get rejected by HW cull, only a tiny minority reach the edge of VCS.
for this reason, we have a wider frustum to better approximate (not calculated precisely) if polys get actually close to the edges.
now we could just use wide frustum only in clipping, check if clipping is required with the wide one, as well as clip with the wide one.
however this turned out to be slower, as a lot of the polygons that are completely out of regular frustum get through and get rendered,
and in addition polygons that clip the wider frustum might be completely out of view too so it's wasteful to clip them at all.
the currently fastest system uses wide frustum to check if a poly should proceed to clipping, if not then it gets drawn fast, then
polygons that do require clipping are then clipped using the accurate view frustum, this allows for vast majority of them to be rejected
when they fall completely outside the view. as a result the amount of actually clipped polygons ends up being extremely low.
this is fast.
*/
static ScePspFMatrix4 wide_projection_view_matrix __attribute__((aligned(16)));
static frustum_t wide_projection_view_frustum __attribute__((aligned(16)));
static frustum_t wide_clipping_frustum __attribute__((aligned(16)));
// The temporary working buffers.
static const std::size_t max_clipped_vertices = 32;
@ -186,13 +207,24 @@ namespace quake
);
}
void begin_frame()
void begin_frame(float regularfov, float wideclippingfov, float screenaspect)
{
// Get the projection matrix.
sceGumMatrixMode(GU_PROJECTION);
sceGumLoadIdentity();
sceGumPerspective(regularfov + 1.0f, screenaspect, 6, 4096); // add + 1.0f to reduce the 1px lines at the edge of viewport when polys get clipped
sceGumUpdateMatrix();
ScePspFMatrix4 proj;
sceGumStoreMatrix(&proj);
sceGumLoadIdentity();
sceGumPerspective(wideclippingfov, screenaspect, 6, 4096);
sceGumUpdateMatrix();
ScePspFMatrix4 wide_proj;
sceGumStoreMatrix(&wide_proj);
// Get the view matrix.
sceGumMatrixMode(GU_VIEW);
ScePspFMatrix4 view;
@ -203,9 +235,11 @@ namespace quake
// Combine the two matrices (multiply projection by view).
gumMultMatrix(&projection_view_matrix, &proj, &view);
gumMultMatrix(&wide_projection_view_matrix, &wide_proj, &view);
// Calculate and cache the clipping frustum.
calculate_frustum(projection_view_matrix, &projection_view_frustum);
calculate_frustum(wide_projection_view_matrix, &wide_projection_view_frustum);
__asm__ volatile (
"ulv.q C700, %4\n" // Load plane into register
@ -225,6 +259,25 @@ namespace quake
"m"( projection_view_frustum[plane_index_right] ),
"m"( projection_view_frustum[plane_index_top] )
);
__asm__ volatile (
"ulv.q C500, %4\n" // Load plane into register
"ulv.q C510, %5\n" // Load plane into register
"ulv.q C520, %6\n" // Load plane into register
"ulv.q C530, %7\n" // Load plane into register
"sv.q C500, %0\n" // Store plane from register
"sv.q C510, %1\n" // Store plane from register
"sv.q C520, %2\n" // Store plane from register
"sv.q C530, %3\n" // Store plane from register
: "=m"( wide_clipping_frustum[plane_index_bottom] ),
"=m"( wide_clipping_frustum[plane_index_left] ),
"=m"( wide_clipping_frustum[plane_index_right] ),
"=m"( wide_clipping_frustum[plane_index_top] )
: "m"( wide_projection_view_frustum[plane_index_bottom] ),
"m"( wide_projection_view_frustum[plane_index_left] ),
"m"( wide_projection_view_frustum[plane_index_right] ),
"m"( wide_projection_view_frustum[plane_index_top] )
);
}
void begin_brush_model()
@ -250,6 +303,24 @@ namespace quake
"m"(clipping_frustum[plane_index_right]),
"m"(clipping_frustum[plane_index_top])
);
// Combine the matrices (multiply projection-view by model).
ScePspFMatrix4 wide_projection_view_model_matrix;
gumMultMatrix(&wide_projection_view_model_matrix, &wide_projection_view_matrix, &model_matrix);
// Calculate the clipping frustum.
calculate_frustum(wide_projection_view_model_matrix, &wide_clipping_frustum);
__asm__ volatile (
"ulv.q C500, %0\n" // Load plane into register
"ulv.q C510, %1\n" // Load plane into register
"ulv.q C520, %2\n" // Load plane into register
"ulv.q C530, %3\n" // Load plane into register
:: "m"(wide_clipping_frustum[plane_index_bottom]),
"m"(wide_clipping_frustum[plane_index_left]),
"m"(wide_clipping_frustum[plane_index_right]),
"m"(wide_clipping_frustum[plane_index_top])
);
}
void end_brush_model()
@ -273,9 +344,27 @@ namespace quake
"m"( projection_view_frustum[plane_index_right] ),
"m"( projection_view_frustum[plane_index_top] )
);
__asm__ volatile (
"ulv.q C500, %4\n" // Load plane into register
"ulv.q C510, %5\n" // Load plane into register
"ulv.q C520, %6\n" // Load plane into register
"ulv.q C530, %7\n" // Load plane into register
"sv.q C500, %0\n" // Store plane from register
"sv.q C510, %1\n" // Store plane from register
"sv.q C520, %2\n" // Store plane from register
"sv.q C530, %3\n" // Store plane from register
: "=m"( wide_clipping_frustum[plane_index_bottom] ),
"=m"( wide_clipping_frustum[plane_index_left] ),
"=m"( wide_clipping_frustum[plane_index_right] ),
"=m"( wide_clipping_frustum[plane_index_top] )
: "m"( wide_projection_view_frustum[plane_index_bottom] ),
"m"( wide_projection_view_frustum[plane_index_left] ),
"m"( wide_projection_view_frustum[plane_index_right] ),
"m"( wide_projection_view_frustum[plane_index_top] )
);
}
// Is clipping required?
bool is_clipping_required(const struct glvert_s* vertices, std::size_t vertex_count)
{
int res;
@ -293,7 +382,7 @@ namespace quake
"lv.s S610, 8($8)\n" // S610 = v[i].xyz[0]
"lv.s S611, 12($8)\n" // S611 = v[i].xyz[1]
"lv.s S612, 16($8)\n" // S612 = v[i].xyz[2]
"vhtfm4.q C620, M700, C610\n" // C620 = frustrum * v[i].xyz
"vhtfm4.q C620, M500, C610\n" // C620 = frustrum * v[i].xyz, note: 500 is wide frustum, 700 is regular frustum
"vcmp.q LT, C620, C600\n" // S620 < 0.0f || S621 < 0.0f || S622 < 0.0f || S623 < 0.0f
"bvt 4, 1f\n" // if ( CC[4] == 1 ) jump to exit
"addiu $8, $8, 20\n" // $8 = $8 + 20( sizeof( gu_vert_t ) ) ( delay slot )

2
source/psp/clipping.hpp
View file

@ -30,7 +30,7 @@ namespace quake
namespace clipping
{
// Calculates clipping planes from the GU view and projection matrices.
void begin_frame();
void begin_frame(float regularfov, float wideclippingfov, float screenaspect);
// Calculates clipping planes from the GU view and projection matrices.
void begin_brush_model();

14
source/psp/video_hardware_main.cpp
View file

@ -3832,7 +3832,19 @@ void R_RenderScene (void)
sceGumMatrixMode(GU_MODEL);
clipping::begin_frame();
// the value 2.2 is a bit of a sweet spot found by trial and error
// the bigger the number, the more polys skip clipping entirely and less polys also rejected
// the smaller the number, the more polys get clipped and by extension more polys also rejected
// at a sweet spot we want to maximize rejected polys but minimize (clipped - rejected) amount at the same time
// it's a balancing act and every change has to be benchmarked. between 2.5, 2.2 and 2.0, 2.2 was the fastest.
clipping::begin_frame(fovy, fmin(165.f, fovy * 2.2f), fovx);
sceGumMatrixMode(GU_PROJECTION);
sceGumLoadIdentity();
sceGumPerspective(fovy, fovx, 4, r_maxrange.value);
sceGumUpdateMatrix();
sceGumMatrixMode(GU_MODEL);
// set drawing parms
sceGuDisable(GU_BLEND);