radeonsi: use higher subpixel precision (QUANT_MODE) for smaller viewports

diff --git a/src/gallium/drivers/radeonsi/si_get.c b/src/gallium/drivers/radeonsi/si_get.c
index a87cb3c..ac302b8 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_get.c
+++ b/src/gallium/drivers/radeonsi/si_get.c
@@ -335,7 +335,9 @@ static float si_get_paramf(struct pipe_screen* pscreen, enum pipe_capf param)
        case PIPE_CAPF_MAX_LINE_WIDTH_AA:
        case PIPE_CAPF_MAX_POINT_WIDTH:
        case PIPE_CAPF_MAX_POINT_WIDTH_AA:
-               return 8192.0f;
+               /* This depends on the quant mode, though the precise interactions
+                * are unknown. */
+               return 2048;
        case PIPE_CAPF_MAX_TEXTURE_ANISOTROPY:
                return 16.0f;
        case PIPE_CAPF_MAX_TEXTURE_LOD_BIAS:

diff --git a/src/gallium/drivers/radeonsi/si_pipe.h b/src/gallium/drivers/radeonsi/si_pipe.h
index 93082e2..7e15412 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_pipe.h
+++ b/src/gallium/drivers/radeonsi/si_pipe.h
@@ -603,11 +603,19 @@ struct si_framebuffer {
        bool                            DB_has_shader_readable_metadata;
 };
 
+enum si_quant_mode {
+       /* This is the list we want to support. */
+       SI_QUANT_MODE_16_8_FIXED_POINT_1_256TH,
+       SI_QUANT_MODE_14_10_FIXED_POINT_1_1024TH,
+       SI_QUANT_MODE_12_12_FIXED_POINT_1_4096TH,
+};
+
 struct si_signed_scissor {
        int minx;
        int miny;
        int maxx;
        int maxy;
+       enum si_quant_mode quant_mode;
 };
 
 struct si_scissors {

diff --git a/src/gallium/drivers/radeonsi/si_state_viewport.c b/src/gallium/drivers/radeonsi/si_state_viewport.c
index c69a56d..819c773 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_state_viewport.c
+++ b/src/gallium/drivers/radeonsi/si_state_viewport.c
@@ -107,6 +107,7 @@ static void si_scissor_make_union(struct si_signed_scissor *out,
        out->miny = MIN2(out->miny, in->miny);
        out->maxx = MAX2(out->maxx, in->maxx);
        out->maxy = MAX2(out->maxy, in->maxy);
+       out->quant_mode = MIN2(out->quant_mode, in->quant_mode);
 }
 
 static void si_emit_one_scissor(struct si_context *ctx,
@@ -145,9 +146,6 @@ static void si_emit_one_scissor(struct si_context *ctx,
                        S_028254_BR_Y(final.maxy));
 }
 
-/* the range is [-MAX, MAX] */
-#define SI_MAX_VIEWPORT_RANGE 32768
-
 static void si_emit_guardband(struct si_context *ctx)
 {
        const struct si_state_rasterizer *rs = ctx->queued.named.rasterizer;
@@ -168,6 +166,13 @@ static void si_emit_guardband(struct si_context *ctx)
                vp_as_scissor = ctx->viewports.as_scissor[0];
        }
 
+       /* Blits don't set the viewport state. The vertex shader determines
+        * the viewport size by scaling the coordinates, so we don't know
+        * how large the viewport is. Assume the worst case.
+        */
+       if (ctx->vs_disables_clipping_viewport)
+               vp_as_scissor.quant_mode = SI_QUANT_MODE_16_8_FIXED_POINT_1_256TH;
+
        /* Determine the optimal hardware screen offset to center the viewport
         * within the viewport range in order to maximize the guardband size.
         */
@@ -211,9 +216,11 @@ static void si_emit_guardband(struct si_context *ctx)
         * This is done by applying the inverse viewport transformation
         * on the viewport limits to get those limits in clip space.
         *
-        * Use a limit one pixel smaller to allow for some precision error.
+        * The viewport range is [-max_viewport_size/2, max_viewport_size/2].
         */
-       max_range = SI_MAX_VIEWPORT_RANGE - 1;
+       static unsigned max_viewport_size[] = {65535, 16383, 4095};
+       assert(vp_as_scissor.quant_mode < ARRAY_SIZE(max_viewport_size));
+       max_range = max_viewport_size[vp_as_scissor.quant_mode] / 2;
        left   = (-max_range - vp.translate[0]) / vp.scale[0];
        right  = ( max_range - vp.translate[0]) / vp.scale[0];
        top    = (-max_range - vp.translate[1]) / vp.scale[1];
@@ -262,7 +269,8 @@ static void si_emit_guardband(struct si_context *ctx)
        radeon_opt_set_context_reg(ctx, R_028BE4_PA_SU_VTX_CNTL,
                                   SI_TRACKED_PA_SU_VTX_CNTL,
                                   S_028BE4_PIX_CENTER(rs->half_pixel_center) |
-                                  S_028BE4_QUANT_MODE(V_028BE4_X_16_8_FIXED_POINT_1_256TH));
+                                  S_028BE4_QUANT_MODE(V_028BE4_X_16_8_FIXED_POINT_1_256TH +
+                                                      vp_as_scissor.quant_mode));
 }
 
 static void si_emit_scissors(struct si_context *ctx)
@@ -311,10 +319,33 @@ static void si_set_viewport_states(struct pipe_context *pctx,
 
        for (i = 0; i < num_viewports; i++) {
                unsigned index = start_slot + i;
+               struct si_signed_scissor *scissor = &ctx->viewports.as_scissor[index];
 
                ctx->viewports.states[index] = state[i];
-               si_get_scissor_from_viewport(ctx, &state[i],
-                                            &ctx->viewports.as_scissor[index]);
+
+               si_get_scissor_from_viewport(ctx, &state[i], scissor);
+
+               unsigned w = scissor->maxx - scissor->minx;
+               unsigned h = scissor->maxy - scissor->miny;
+               unsigned max_extent = MAX2(w, h);
+
+               /* Determine the best quantization mode (subpixel precision),
+                * but also leave enough space for the guardband.
+                *
+                * Note that primitive binning requires QUANT_MODE == 16_8 on Vega10
+                * and Raven1. What we do depends on the chip:
+                * - Vega10: Never use primitive binning.
+                * - Raven1: Always use QUANT_MODE == 16_8.
+                */
+               if (ctx->family == CHIP_RAVEN)
+                       max_extent = 16384; /* Use QUANT_MODE == 16_8. */
+
+               if (max_extent <= 1024) /* 4K scanline area for guardband */
+                       scissor->quant_mode = SI_QUANT_MODE_12_12_FIXED_POINT_1_4096TH;
+               else if (max_extent <= 4096) /* 16K scanline area for guardband */
+                       scissor->quant_mode = SI_QUANT_MODE_14_10_FIXED_POINT_1_1024TH;
+               else /* 64K scanline area for guardband */
+                       scissor->quant_mode = SI_QUANT_MODE_16_8_FIXED_POINT_1_256TH;
        }
 
        mask = ((1 << num_viewports) - 1) << start_slot;
@@ -565,4 +596,7 @@ void si_init_viewport_functions(struct si_context *ctx)
        ctx->b.set_scissor_states = si_set_scissor_states;
        ctx->b.set_viewport_states = si_set_viewport_states;
        ctx->b.set_window_rectangles = si_set_window_rectangles;
+
+       for (unsigned i = 0; i < 16; i++)
+               ctx->viewports.as_scissor[i].quant_mode = SI_QUANT_MODE_16_8_FIXED_POINT_1_256TH;
 }