st/mesa: add support for GL_ARB_viewport_array (v0.2)

this just ties the mesa code to the pre-existing gallium interface,
I'm not sure what to do with the CSO stuff yet.

0.2: fix min/max bounds

Acked-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Dave Airlie <airlied@redhat.com>

5 files changed, 73 insertions, 56 deletions

diff --git a/src/mesa/state_tracker/st_atom_scissor.c b/src/mesa/state_tracker/st_atom_scissor.c
index a1f72da47e0..a19ade1fafe 100644
--- a/src/mesa/state_tracker/st_atom_scissor.c
+++ b/src/mesa/state_tracker/st_atom_scissor.c
@@ -43,51 +43,56 @@
 static void
 update_scissor( struct st_context *st )
 {
-   struct pipe_scissor_state scissor;
+   struct pipe_scissor_state scissor[PIPE_MAX_VIEWPORTS];
    const struct gl_context *ctx = st->ctx;
    const struct gl_framebuffer *fb = ctx->DrawBuffer;
    GLint miny, maxy;
+   int i;
+   bool changed = false;
+   for (i = 0 ; i < ctx->Const.MaxViewports; i++) {
+      scissor[i].minx = 0;
+      scissor[i].miny = 0;
+      scissor[i].maxx = fb->Width;
+      scissor[i].maxy = fb->Height;
 
-   scissor.minx = 0;
-   scissor.miny = 0;
-   scissor.maxx = fb->Width;
-   scissor.maxy = fb->Height;
+      if (ctx->Scissor.EnableFlags & (1 << i)) {
+         /* need to be careful here with xmax or ymax < 0 */
+         GLint xmax = MAX2(0, ctx->Scissor.ScissorArray[i].X + ctx->Scissor.ScissorArray[i].Width);
+         GLint ymax = MAX2(0, ctx->Scissor.ScissorArray[i].Y + ctx->Scissor.ScissorArray[i].Height);
 
-   if (ctx->Scissor.EnableFlags & 1) {
-      /* need to be careful here with xmax or ymax < 0 */
-      GLint xmax = MAX2(0, ctx->Scissor.ScissorArray[0].X + ctx->Scissor.ScissorArray[0].Width);
-      GLint ymax = MAX2(0, ctx->Scissor.ScissorArray[0].Y + ctx->Scissor.ScissorArray[0].Height);
+         if (ctx->Scissor.ScissorArray[i].X > (GLint)scissor[i].minx)
+            scissor[i].minx = ctx->Scissor.ScissorArray[i].X;
+         if (ctx->Scissor.ScissorArray[i].Y > (GLint)scissor[i].miny)
+            scissor[i].miny = ctx->Scissor.ScissorArray[i].Y;
 
-      if (ctx->Scissor.ScissorArray[0].X > (GLint)scissor.minx)
-         scissor.minx = ctx->Scissor.ScissorArray[0].X;
-      if (ctx->Scissor.ScissorArray[0].Y > (GLint)scissor.miny)
-         scissor.miny = ctx->Scissor.ScissorArray[0].Y;
+         if (xmax < (GLint) scissor[i].maxx)
+            scissor[i].maxx = xmax;
+         if (ymax < (GLint) scissor[i].maxy)
+            scissor[i].maxy = ymax;
+         
+         /* check for null space */
+         if (scissor[i].minx >= scissor[i].maxx || scissor[i].miny >= scissor[i].maxy)
+            scissor[i].minx = scissor[i].miny = scissor[i].maxx = scissor[i].maxy = 0;
+      }
 
-      if (xmax < (GLint) scissor.maxx)
-         scissor.maxx = xmax;
-      if (ymax < (GLint) scissor.maxy)
-         scissor.maxy = ymax;
+      /* Now invert Y if needed.
+       * Gallium drivers use the convention Y=0=top for surfaces.
+       */
+      if (st_fb_orientation(fb) == Y_0_TOP) {
+         miny = fb->Height - scissor[i].maxy;
+         maxy = fb->Height - scissor[i].miny;
+         scissor[i].miny = miny;
+         scissor[i].maxy = maxy;
+      }
 
-      /* check for null space */
-      if (scissor.minx >= scissor.maxx || scissor.miny >= scissor.maxy)
-         scissor.minx = scissor.miny = scissor.maxx = scissor.maxy = 0;
-   }
-
-   /* Now invert Y if needed.
-    * Gallium drivers use the convention Y=0=top for surfaces.
-    */
-   if (st_fb_orientation(fb) == Y_0_TOP) {
-      miny = fb->Height - scissor.maxy;
-      maxy = fb->Height - scissor.miny;
-      scissor.miny = miny;
-      scissor.maxy = maxy;
-   }
-
-   if (memcmp(&scissor, &st->state.scissor, sizeof(scissor)) != 0) {
-      /* state has changed */
-      st->state.scissor = scissor;  /* struct copy */
-      st->pipe->set_scissor_states(st->pipe, 0, 1, &scissor); /* activate */
+      if (memcmp(&scissor[i], &st->state.scissor[i], sizeof(scissor)) != 0) {
+         /* state has changed */
+         st->state.scissor[i] = scissor[i];  /* struct copy */
+         changed = true;
+      }
    }
+   if (changed)
+      st->pipe->set_scissor_states(st->pipe, 0, ctx->Const.MaxViewports, scissor); /* activate */
 }
 
 
diff --git a/src/mesa/state_tracker/st_atom_viewport.c b/src/mesa/state_tracker/st_atom_viewport.c
index 8c6d679a041..7584f9b3d55 100644
--- a/src/mesa/state_tracker/st_atom_viewport.c
+++ b/src/mesa/state_tracker/st_atom_viewport.c
@@ -43,7 +43,7 @@ update_viewport( struct st_context *st )
 {
    struct gl_context *ctx = st->ctx;
    GLfloat yScale, yBias;
-
+   int i;
    /* _NEW_BUFFERS
     */
    if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {
@@ -61,26 +61,29 @@ update_viewport( struct st_context *st )
 
    /* _NEW_VIEWPORT 
     */
+   for (i = 0; i < ctx->Const.MaxViewports; i++)
    {
-      GLfloat x = ctx->ViewportArray[0].X;
-      GLfloat y = ctx->ViewportArray[0].Y;
-      GLfloat z = ctx->ViewportArray[0].Near;
-      GLfloat half_width = ctx->ViewportArray[0].Width * 0.5f;
-      GLfloat half_height = ctx->ViewportArray[0].Height * 0.5f;
-      GLfloat half_depth = (GLfloat)(ctx->ViewportArray[0].Far - ctx->ViewportArray[0].Near) * 0.5f;
+      GLfloat x = ctx->ViewportArray[i].X;
+      GLfloat y = ctx->ViewportArray[i].Y;
+      GLfloat z = ctx->ViewportArray[i].Near;
+      GLfloat half_width = ctx->ViewportArray[i].Width * 0.5f;
+      GLfloat half_height = ctx->ViewportArray[i].Height * 0.5f;
+      GLfloat half_depth = (GLfloat)(ctx->ViewportArray[i].Far - ctx->ViewportArray[i].Near) * 0.5f;
       
-      st->state.viewport.scale[0] = half_width;
-      st->state.viewport.scale[1] = half_height * yScale;
-      st->state.viewport.scale[2] = half_depth;
-      st->state.viewport.scale[3] = 1.0;
-
-      st->state.viewport.translate[0] = half_width + x;
-      st->state.viewport.translate[1] = (half_height + y) * yScale + yBias;
-      st->state.viewport.translate[2] = half_depth + z;
-      st->state.viewport.translate[3] = 0.0;
+      st->state.viewport[i].scale[0] = half_width;
+      st->state.viewport[i].scale[1] = half_height * yScale;
+      st->state.viewport[i].scale[2] = half_depth;
+      st->state.viewport[i].scale[3] = 1.0;
 
-      cso_set_viewport(st->cso_context, &st->state.viewport);
+      st->state.viewport[i].translate[0] = half_width + x;
+      st->state.viewport[i].translate[1] = (half_height + y) * yScale + yBias;
+      st->state.viewport[i].translate[2] = half_depth + z;
+      st->state.viewport[i].translate[3] = 0.0;
    }
+
+   cso_set_viewport(st->cso_context, &st->state.viewport[0]);
+   if (ctx->Const.MaxViewports > 1)
+      st->pipe->set_viewport_states(st->pipe, 1, ctx->Const.MaxViewports - 1, &st->state.viewport[1]);
 }
 
 
diff --git a/src/mesa/state_tracker/st_context.h b/src/mesa/state_tracker/st_context.h
index 996e0c6bce9..9c699a015c0 100644
--- a/src/mesa/state_tracker/st_context.h
+++ b/src/mesa/state_tracker/st_context.h
@@ -115,8 +115,8 @@ struct st_context
          unsigned size;
       } constants[PIPE_SHADER_TYPES];
       struct pipe_framebuffer_state framebuffer;
-      struct pipe_scissor_state scissor;
-      struct pipe_viewport_state viewport;
+      struct pipe_scissor_state scissor[PIPE_MAX_VIEWPORTS];
+      struct pipe_viewport_state viewport[PIPE_MAX_VIEWPORTS];
       unsigned sample_mask;
 
       GLuint poly_stipple[32];  /**< In OpenGL's bottom-to-top order */
diff --git a/src/mesa/state_tracker/st_draw_feedback.c b/src/mesa/state_tracker/st_draw_feedback.c
index 09cd9511d9b..177f6b5aefa 100644
--- a/src/mesa/state_tracker/st_draw_feedback.c
+++ b/src/mesa/state_tracker/st_draw_feedback.c
@@ -156,7 +156,7 @@ st_feedback_draw_vbo(struct gl_context *ctx,
     * code sends state updates to the pipe, not to our private draw module.
     */
    assert(draw);
-   draw_set_viewport_states(draw, 0, 1, &st->state.viewport);
+   draw_set_viewport_states(draw, 0, 1, &st->state.viewport[0]);
    draw_set_clip_state(draw, &st->state.clip);
    draw_set_rasterizer_state(draw, &st->state.rasterizer, NULL);
    draw_bind_vertex_shader(draw, st->vp_variant->draw_shader);
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index f9b7a445f1f..1f391c9f0dd 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -779,4 +779,13 @@ void st_init_extensions(struct st_context *st)
       if (!ctx->Extensions.EXT_transform_feedback)
          ctx->Const.DisableVaryingPacking = GL_TRUE;
    }
+
+   if (ctx->API == API_OPENGL_CORE) {
+      ctx->Const.MaxViewports = screen->get_param(screen, PIPE_CAP_MAX_VIEWPORTS);
+      if (ctx->Const.MaxViewports >= 16) {
+         ctx->Const.ViewportBounds.Min = -(float)ctx->Const.MaxViewportWidth;
+         ctx->Const.ViewportBounds.Max = ctx->Const.MaxViewportWidth;
+         ctx->Extensions.ARB_viewport_array = GL_TRUE;
+      }
+   }
 }