meta: Stop frobbing MatrixMode

   text     data     bss      dec    hex  filename
12243510 1344936 1290748 14879194 e309da  before/lib64/dri/i965_dri.so
12243446 1344936 1290748 14879130 e3099a  after/lib64/dri/i965_dri.so

v2: Use _mesa_load_matrix to set the projection matrix instead of
frobbing dirty bits directly.  Suggested by Jason.  Clean up some
comments in the neighborhood.  Since glOrtho isn't called, there's no
point in mentioning it in the comment.  Only _mesa_load_identity_matrix
on the projection matrix when it isn't set to an ortho matrix.

Reviewed-by: Jason Ekstrand <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/856>

2 files changed, 21 insertions, 33 deletions

diff --git a/src/mesa/drivers/common/meta.c b/src/mesa/drivers/common/meta.c
index 5efe30dead2..aecc6d10b1c 100644
--- a/src/mesa/drivers/common/meta.c
+++ b/src/mesa/drivers/common/meta.c
@@ -686,31 +686,31 @@ _mesa_meta_begin(struct gl_context *ctx, GLbitfield state)
    }
 
    if (state & MESA_META_TRANSFORM) {
-      GLuint activeTexture = ctx->Texture.CurrentUnit;
       memcpy(save->ModelviewMatrix, ctx->ModelviewMatrixStack.Top->m,
              16 * sizeof(GLfloat));
       memcpy(save->ProjectionMatrix, ctx->ProjectionMatrixStack.Top->m,
              16 * sizeof(GLfloat));
       memcpy(save->TextureMatrix, ctx->TextureMatrixStack[0].Top->m,
              16 * sizeof(GLfloat));
-      save->MatrixMode = ctx->Transform.MatrixMode;
+
       /* set 1:1 vertex:pixel coordinate transform */
-      _mesa_ActiveTexture(GL_TEXTURE0);
-      _mesa_MatrixMode(GL_TEXTURE);
-      _mesa_LoadIdentity();
-      _mesa_ActiveTexture(GL_TEXTURE0 + activeTexture);
-      _mesa_MatrixMode(GL_MODELVIEW);
-      _mesa_LoadIdentity();
-      _mesa_MatrixMode(GL_PROJECTION);
-      _mesa_LoadIdentity();
-
-      /* glOrtho with width = 0 or height = 0 generates GL_INVALID_VALUE.
-       * This can occur when there is no draw buffer.
+      _mesa_load_identity_matrix(ctx, &ctx->ModelviewMatrixStack);
+      _mesa_load_identity_matrix(ctx, &ctx->TextureMatrixStack[0]);
+
+      /* _math_float_ortho with width = 0 or height = 0 will have a divide by
+       * zero.  This can occur when there is no draw buffer.
        */
-      if (ctx->DrawBuffer->Width != 0 && ctx->DrawBuffer->Height != 0)
-         _mesa_Ortho(0.0, ctx->DrawBuffer->Width,
-                     0.0, ctx->DrawBuffer->Height,
-                     -1.0, 1.0);
+      if (ctx->DrawBuffer->Width != 0 && ctx->DrawBuffer->Height != 0) {
+         float m[16];
+
+         _math_float_ortho(m,
+                           0.0f, (float) ctx->DrawBuffer->Width,
+                           0.0f, (float) ctx->DrawBuffer->Height,
+                           -1.0f, 1.0f);
+         _mesa_load_matrix(ctx, &ctx->ProjectionMatrixStack, m);
+      } else {
+         _mesa_load_identity_matrix(ctx, &ctx->ProjectionMatrixStack);
+      }
 
       if (ctx->Extensions.ARB_clip_control) {
          save->ClipOrigin = ctx->Transform.ClipOrigin;
@@ -1102,19 +1102,9 @@ _mesa_meta_end(struct gl_context *ctx)
    }
 
    if (state & MESA_META_TRANSFORM) {
-      GLuint activeTexture = ctx->Texture.CurrentUnit;
-      _mesa_ActiveTexture(GL_TEXTURE0);
-      _mesa_MatrixMode(GL_TEXTURE);
-      _mesa_LoadMatrixf(save->TextureMatrix);
-      _mesa_ActiveTexture(GL_TEXTURE0 + activeTexture);
-
-      _mesa_MatrixMode(GL_MODELVIEW);
-      _mesa_LoadMatrixf(save->ModelviewMatrix);
-
-      _mesa_MatrixMode(GL_PROJECTION);
-      _mesa_LoadMatrixf(save->ProjectionMatrix);
-
-      _mesa_MatrixMode(save->MatrixMode);
+      _mesa_load_matrix(ctx, &ctx->ModelviewMatrixStack, save->ModelviewMatrix);
+      _mesa_load_matrix(ctx, &ctx->ProjectionMatrixStack, save->ProjectionMatrix);
+      _mesa_load_matrix(ctx, &ctx->TextureMatrixStack[0], save->TextureMatrix);
 
       if (ctx->Extensions.ARB_clip_control)
          _mesa_ClipControl(save->ClipOrigin, save->ClipDepthMode);
@@ -1500,8 +1490,7 @@ _mesa_meta_setup_ff_tnl_for_blit(struct gl_context *ctx,
                                    0);
 
    /* setup projection matrix */
-   _mesa_MatrixMode(GL_PROJECTION);
-   _mesa_LoadIdentity();
+   _mesa_load_identity_matrix(ctx, &ctx->ProjectionMatrixStack);
 }
 
 /**
diff --git a/src/mesa/drivers/common/meta.h b/src/mesa/drivers/common/meta.h
index 511ffb45a78..6fefbeb7880 100644
--- a/src/mesa/drivers/common/meta.h
+++ b/src/mesa/drivers/common/meta.h
@@ -133,7 +133,6 @@ struct save_state
    struct gl_stencil_attrib Stencil;
 
    /** MESA_META_TRANSFORM */
-   GLenum MatrixMode;
    GLfloat ModelviewMatrix[16];
    GLfloat ProjectionMatrix[16];
    GLfloat TextureMatrix[16];