Dreamcast: Slightly optimise performance by avoiding separate viewport transform

misc/dreamcast/VertexDraw.S

@@ -6,16 +6,6 @@
 ! r13 = cur vertex
 ! r14 = next vertex (prefetch)
 
-!fr12 = VIEWPORT_HWIDTH
-!fr13 = VIEWPORT_HHEIGHT
-!fr14 = VIEWPORT_X_PLUS_HWIDTH
-!fr15 = VIEWPORT_Y_PLUS_HHEIGHT
-
-#define F_HW fr12
-#define F_HH fr13
-#define F_XP fr14
-#define F_YP fr15
-
 #define R_VTX        r10
 #define R_EOL        r11
 #define REG_CMD_VTX  r10
@@ -51,42 +41,8 @@
 	add     #32,r8      ! EX, SQ += 32
 .endm
 
-
-! Pushes a vertex to the store queue
-!   CLOBBERS: fr0, fr4, fr5
-!   INPUTS:   R (vertex)
-!   OUTPUTS:
-! TODO optimise greatly  
-.macro ViewportTransform R
-! INVERSE W CALCULATION
-    add #28, \R       ! EX, \R  = &vertex->w
-    fmov.s  @\R,fr0   ! LS, fr0 = vertex->w
-    fmul    fr0,fr0   ! FE, fr0 = fr0 * fr0
-    add #-24, \R      ! EX, \R  = &vertex->x
-    fsrra   fr0       ! FE, fr0 = 1 / sqrt(fr0) -> 1 / vertex->w
-
-! TRANSFORM X
-    fmov.s @\R,fr4    ! LS, fr4 = vertex->x
-    fmov  F_XP,fr5    ! LS, fr5 = VIEWPORT_X_PLUS_HWIDTH
-    fmul  F_HW,fr4    ! FE, fr4 = VIEWPORT_HWIDTH * vertex->x
-    fmac  fr0,fr4,fr5 ! FE, fr5 = fr0 * fr4 + fr5 -- (X * F * hwidth) + x_plus_hwidth
-    fmov.s fr5,@\R    ! LS, vertex->x = fr5
-    add #4, \R        ! EX, \R  = &vertex->y
-
-! TRANSFORM Y
-    fmov.s @\R,fr4    ! LS, fr4 = vertex->y
-    fmov  F_YP,fr5    ! LS, fr5  = VIEWPORT_Y_PLUS_HHEIGHT
-    fmul  F_HH,fr4    ! FE, fr4  = VIEWPORT_HHEIGHT * vertex->y
-    fmac  fr0,fr4,fr5 ! FE, fr5  = fr0 * fr4 + fr5 -- (Y * F * hheight) + y_plus_hheight
-    fmov.s fr5,@\R    ! LS, vertex->y = fr5
-    add #4, \R        ! EX, \R  = &vertex->z
-
-! ASSIGN Z
-    fmov.s fr0,@\R    ! LS, vertex->z = fr0
-    add #-12, \R      ! EX, \R -= 12 (back to start of vertex)
-.endm
-
 ! Transforms then pushes a vertex to the store queue
+! note: Vertices are assumed as pre viewport transformed already
 !   CLOBBERS: r2, fr0, fr4, fr5
 !   INPUTS:   R (vertex), r8 (SQ global)
 !   OUTPUTS:  R, r8 altered
@@ -109,24 +65,20 @@
 
 ! TRANSFORM X
     fmov.s @\R,fr4    ! LS, fr4 = SRC->x
-    fmov  F_XP,fr5    ! LS, fr5 = VIEWPORT_X_PLUS_HWIDTH
+    fmul   fr0,fr4    ! FE, fr4 = invW * SRC->x
-    fmul  F_HW,fr4    ! FE, fr4 = VIEWPORT_HWIDTH * SRC->x
 	mov.l @(20,\R),r2 ! LS, tmp = SRC->bgra
 	mov.l r2,@(20,r8) ! LS, SRC->bgra = tmp
-    fmac  fr0,fr4,fr5 ! FE, fr5 = invW * fr4 + fr5 -- (X * F * hwidth) + x_plus_hwidth
     add    #4, \R     ! EX, SRC += 4
-    fmov.s fr5,@r8    ! LS, DST->x = fr5
+    fmov.s fr4,@r8    ! LS, DST->x = fr4
 
 ! TRANSFORM Y
     fmov.s @\R,fr4    ! LS, fr4  = SRC->y
-    fmov  F_YP,fr5    ! LS, fr5  = VIEWPORT_Y_PLUS_HHEIGHT
-    fmul  F_HH,fr4    ! FE, fr4  = VIEWPORT_HHEIGHT * SRC->y
     add    #8, r8     ! EX, DST += 8
+    fmul   fr0,fr4    ! FE, fr4 = invW * SRC->y
     fmov.s fr0,@r8    ! LS, DST->z = invW
-    fmac  fr0,fr4,fr5 ! FE, fr5  = invW * fr4 + fr5 -- (Y * F * hheight) + y_plus_hheight
     add   #-4, r8     ! EX, DST -= 4
     add   #-8, \R     ! EX, src -= 8 (back to start of vertex)
-    fmov.s fr5,@r8    ! LS, DST->y = fr5
+    fmov.s fr4,@r8    ! LS, DST->y = fr4
 
     add   #-8,r8      ! EX, DST -= 8 (back to start of vertex)	
 	pref    @r8       ! LS, Trigger SQ
@@ -561,17 +513,6 @@ _ProcessVertexList:
 	mov.l   r13,@-r15
 	mov.l   r14,@-r15
 	sts.l    pr,@-r15
-! STORE FPU REGISTERS
-	fmov.s F_HW,@-r15
-	fmov.s F_HH,@-r15
-	fmov.s F_XP,@-r15
-	fmov.s F_YP,@-r15
-! VIEWPORT SETUP
-    mov.l  .VP_1,r0   ! LS, &vp
-    fmov.s	@r0+,F_HW ! LS, vp.HWIDTH
-    fmov.s	@r0+,F_HH ! LS, vp.HHEIGHT
-    fmov.s	@r0+,F_XP ! LS, vp.X_PLUS_HWIDTH
-    fmov.s	@r0+,F_YP ! LS, vp.Y_PLUS_HHEIGHT
 ! REGISTER SETUP
 	mov      r4,r14
 	mov      r4,r13
@@ -583,33 +524,11 @@ _ProcessVertexList:
 	bra     SUBMIT_LOOP
 	add    #-64,r15
 
-! Handles a non-vertex command
+! Submits a PowerVR GPU command
 DO_CMD:
-	mov     r13,r4     ! r4 = CUR
-	mov     r1,r0      ! r0 = MASK
-	cmp/eq  #35,r0     ! T  = MASK == 0x23
-	bt.s    9f         ! if (T) goto 9;
-	nop
-! PowerVR GPU command
 	PushVertex REG_V0
 	bra     NEXT_ITER
 	nop
-! Viewport update command
-9:
-	add      #4,r4
-	mov.l   .VP_1,r2
-	! Load VIEWPORT registers
-	fmov.s  @r4+,F_HW  ! VIEWPORT_HWIDTH  = src->x
-	fmov.s  @r4+,F_HH  ! VIEWPORT_HHEIGHT = src->y
-	fmov.s  @r4+,F_XP  ! VIEWPORT_X_PLUS_HWIDTH  = src->z
-	add      #16,r2
-	fmov.s  @r4+,F_YP  ! VIEWPORT_Y_PLUS_HHEIGHT = src->u
-	! And store to vp global
-	fmov.s  F_YP,@-r2
-	fmov.s  F_XP,@-r2
-	fmov.s  F_HH,@-r2
-	bra     NEXT_ITER
-	fmov.s  F_HW,@-r2
 
 SUBMIT_LOOP:
 	mov.l   @r13,r0   ! FLAGS = CUR->flags
@@ -645,18 +564,6 @@ NEXT_ITER:
 	mov     r14,r13     ! CUR = NEXT 
 
 	add      #64,r15
-! VIEWPORT SAVE
-	mov.l  .VP_1,r0
-	add      #16,r0
-	fmov.s  F_YP,@-r0
-	fmov.s  F_XP,@-r0
- 	fmov.s  F_HH,@-r0
- 	fmov.s  F_HW,@-r0
-! RESTORE FPU REGISTERS
-	fmov.s  @r15+,F_YP
-	fmov.s  @r15+,F_XP
-	fmov.s  @r15+,F_HH
-	fmov.s  @r15+,F_HW
 ! RESTORE CPU REGISTERS
 	lds.l   @r15+,pr
 	mov.l   @r15+,r14

misc/dreamcast/VertexTransform.S

@@ -48,11 +48,6 @@
 !fr5  = y
 !fr6  = z
 !fr7  = w
-!fr8  = VIEWPORT_HWIDTH
-!fr9  = VIEWPORT_HHEIGHT
-!fr10 = VIEWPORT_X_PLUS_HWIDTH
-!fr11 = VIEWPORT_Y_PLUS_HHEIGHT
-
 !fv4  = XYZW
 
 

src/Graphics_Dreamcast.c

@@ -448,11 +448,21 @@ static matrix_t __attribute__((aligned(32))) _proj, _view;
 static float textureOffsetX, textureOffsetY;
 static int textureOffset;
 
+static float vp_scaleX, vp_scaleY, vp_offsetX, vp_offsetY;
+static matrix_t __attribute__((aligned(32))) mat_vp;
+
 void Gfx_LoadMatrix(MatrixType type, const struct Matrix* matrix) {
 	if (type == MATRIX_PROJ) memcpy(&_proj, matrix, sizeof(struct Matrix));
 	if (type == MATRIX_VIEW) memcpy(&_view, matrix, sizeof(struct Matrix));
 
-	mat_load( &_proj);
+	memcpy(&mat_vp, &Matrix_Identity, sizeof(struct Matrix));
+	mat_vp[0][0] = vp_scaleX;
+	mat_vp[1][1] = vp_scaleY;
+	mat_vp[3][0] = vp_offsetX;
+	mat_vp[3][1] = vp_offsetY;
+
+	mat_load(&mat_vp);
+	mat_apply(&_proj);
 	mat_apply(&_view);
 }
 
@@ -645,13 +655,10 @@ static void PushCommand(void* cmd) {
 }
 
 void Gfx_SetViewport(int x, int y, int w, int h) {
-	Vertex c;
+	vp_scaleX  = w *  0.5f; // hwidth
-	c.flags = PVR_CMD_USERCLIP | 0x23;
+	vp_scaleY  = h * -0.5f; // hheight
-	c.x = w *  0.5f; // hwidth
+	vp_offsetX = x + w * 0.5f; // x_plus_hwidth
-	c.y = h * -0.5f; // hheight
+	vp_offsetY = y + h * 0.5f; // y_plus_hheight
-	c.z = x + w * 0.5f; // x_plus_hwidth
-	c.u = y + h * 0.5f; // y_plus_hheight
-	PushCommand(&c);
 }
 
 void Gfx_SetScissor(int x, int y, int w, int h) {

third_party/gldc/src/gldc.h

@@ -44,15 +44,6 @@ typedef struct {
 
 #define GL_FORCE_INLINE static __attribute__((always_inline)) inline
 
-typedef struct {
-    float hwidth;  /* width * 0.5f */
-    float hheight; /* height * 0.5f */
-    float x_plus_hwidth;
-    float y_plus_hheight;
-} Viewport;
-
-extern Viewport VIEWPORTS[3];
-
 typedef struct {
     //0
     GLuint   index;

third_party/gldc/src/sh4.c

@@ -8,7 +8,6 @@
 
 #define SQ_BASE_ADDRESS (void*) 0xe0000000
 #define PREFETCH(addr) __builtin_prefetch((addr))
-Viewport vp;
 
 GL_FORCE_INLINE float _glFastInvert(float x) {
     return MATH_fsrra(x * x);
@@ -17,10 +16,10 @@ GL_FORCE_INLINE float _glFastInvert(float x) {
 GL_FORCE_INLINE void _glPerspectiveDivideVertex(Vertex* vertex) {
     const float f = _glFastInvert(vertex->w);
 
-    /* Convert to NDC and apply viewport */
+    /* Convert to NDC (viewport already applied) */
-    vertex->x = (vertex->x * f * vp.hwidth)  + vp.x_plus_hwidth;
+    vertex->x = vertex->x * f;
-    vertex->y = (vertex->y * f * vp.hheight) + vp.y_plus_hheight;
+    vertex->y = vertex->y * f;
-    vertex->z = f;
+    vertex->z = _glFastInvert(vertex->w);
 }
 
 
@@ -377,21 +376,8 @@ static void SubmitClipped(Vertex* v0, Vertex* v1, Vertex* v2, Vertex* v3, uint8_
     }
 }
 
-static __attribute__((noinline)) void HandleCommand(Vertex* v) {
-	if ((v->flags & 0xFF) != 0x23) {
-		_glPushHeaderOrVertex(v);
-		return;
-	}
-
-	vp.hwidth  = v->x;
-	vp.hheight = v->y;
-	vp.x_plus_hwidth  = v->z;
-	vp.y_plus_hheight = v->u;
-}
-
 extern void ProcessVertexList(Vertex* v3, int n, void* sq_addr);
 void SceneListSubmit(Vertex* v3, int n, int type) {
-	vp = VIEWPORTS[type];
     PVR_SET(SPAN_SORT_CFG, 0x0);
 
     //Set PVR DMA registers
@@ -414,7 +400,7 @@ void SceneListSubmit(Vertex* v3, int n, int type) {
         case PVR_CMD_VERTEX:
             continue;
         default:
-            HandleCommand(v3);
+            _glPushHeaderOrVertex(v3);
             continue;
         };
 
@@ -460,5 +446,4 @@ void SceneListSubmit(Vertex* v3, int n, int type) {
     }
 
     _glFlushBuffer();
-	VIEWPORTS[type] = vp;
 }

third_party/gldc/src/state.c

@@ -26,7 +26,6 @@ GLboolean AUTOSORT_ENABLED;
 AlignedVector OP_LIST;
 AlignedVector PT_LIST;
 AlignedVector TR_LIST;
-Viewport VIEWPORTS[3];
 
 void glKosInit() {
     _glInitTextures();