v3dv/cmd_buffer: cache viewport translate/scale

Before that commit we were calling get_viewport_xform to get those
values twice (to emit scissor and viewport), and we found that we
would need that info even more times. So let's just compute that info
when setting the viewport, and reuse the values.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>

src/broadcom/vulkan/v3dv_cmd_buffer.c

@@ -1043,6 +1043,27 @@ v3dv_CmdBindPipeline(VkCommandBuffer commandBuffer,
    }
 }
 
+/* FIXME: C&P from radv. tu has similar code. Perhaps common place? */
+static void
+get_viewport_xform(const VkViewport *viewport,
+                   float scale[3],
+                   float translate[3])
+{
+   float x = viewport->x;
+   float y = viewport->y;
+   float half_width = 0.5f * viewport->width;
+   float half_height = 0.5f * viewport->height;
+   double n = viewport->minDepth;
+   double f = viewport->maxDepth;
+
+   scale[0] = half_width;
+   translate[0] = half_width + x;
+   scale[1] = half_height;
+   translate[1] = half_height + y;
+
+   scale[2] = (f - n);
+   translate[2] = n;
+}
 
 void
 v3dv_CmdSetViewport(VkCommandBuffer commandBuffer,
@@ -1074,6 +1095,12 @@ v3dv_CmdSetViewport(VkCommandBuffer commandBuffer,
    memcpy(state->dynamic.viewport.viewports + firstViewport, pViewports,
           viewportCount * sizeof(*pViewports));
 
+   for (uint32_t i = firstViewport; i < firstViewport + viewportCount; i++) {
+      get_viewport_xform(&state->dynamic.viewport.viewports[i],
+                         state->dynamic.viewport.scale[i],
+                         state->dynamic.viewport.translate[i]);
+   }
+
    cmd_buffer->state.dirty |= V3DV_CMD_DIRTY_DYNAMIC_VIEWPORT;
 }
 
@@ -1104,41 +1131,16 @@ v3dv_CmdSetScissor(VkCommandBuffer commandBuffer,
    cmd_buffer->state.dirty |= V3DV_CMD_DIRTY_DYNAMIC_SCISSOR;
 }
 
-
-/* FIXME: C&P from radv. tu has similar code. Perhaps common place? */
-static void
-get_viewport_xform(const VkViewport *viewport,
-                   float scale[3],
-                   float translate[3])
-{
-   float x = viewport->x;
-   float y = viewport->y;
-   float half_width = 0.5f * viewport->width;
-   float half_height = 0.5f * viewport->height;
-   double n = viewport->minDepth;
-   double f = viewport->maxDepth;
-
-   scale[0] = half_width;
-   translate[0] = half_width + x;
-   scale[1] = half_height;
-   translate[1] = half_height + y;
-
-   scale[2] = (f - n);
-   translate[2] = n;
-}
-
 static void
 emit_scissor(struct v3dv_cmd_buffer *cmd_buffer)
 {
    struct v3dv_dynamic_state *dynamic = &cmd_buffer->state.dynamic;
-   float vptranslate[3];
-   float vpscale[3];
 
    /* FIXME: right now we only support one viewport. viewporst[0] would work
     * now, but would need to change if we allow multiple viewports.
     */
-   get_viewport_xform(&dynamic->viewport.viewports[0],
-                      vpscale, vptranslate);
+   float *vptranslate = dynamic->viewport.translate[0];
+   float *vpscale = dynamic->viewport.scale[0];
 
    float vp_minx = -fabsf(vpscale[0]) + vptranslate[0];
    float vp_maxx = fabsf(vpscale[0]) + vptranslate[0];
@@ -1186,14 +1188,11 @@ static void
 emit_viewport(struct v3dv_cmd_buffer *cmd_buffer)
 {
    struct v3dv_dynamic_state *dynamic = &cmd_buffer->state.dynamic;
-   float vptranslate[3];
-   float vpscale[3];
-
    /* FIXME: right now we only support one viewport. viewporst[0] would work
     * now, would need to change if we allow multiple viewports
     */
-   get_viewport_xform(&dynamic->viewport.viewports[0],
-                      vpscale, vptranslate);
+   float *vptranslate = dynamic->viewport.translate[0];
+   float *vpscale = dynamic->viewport.scale[0];
 
    cl_emit(&cmd_buffer->bcl, CLIPPER_XY_SCALING, clip) {
       clip.viewport_half_width_in_1_256th_of_pixel = vpscale[0] * 256.0f;

src/broadcom/vulkan/v3dv_private.h

@@ -393,6 +393,8 @@ struct v3dv_cmd_buffer_attachment_state {
 struct v3dv_viewport_state {
    uint32_t count;
    VkViewport viewports[MAX_VIEWPORTS];
+   float translate[MAX_VIEWPORTS][3];
+   float scale[MAX_VIEWPORTS][3];
 };
 
 struct v3dv_scissor_state {