1 files changed, 129 insertions, 0 deletions
diff --git a/src/gallium/drivers/r300/r300_render_stencilref.c b/src/gallium/drivers/r300/r300_render_stencilref.c
new file mode 100644
index 00000000000..1f035d64a28
--- /dev/null
+++ b/src/gallium/drivers/r300/r300_render_stencilref.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright 2010 Marek Olšák <[email protected]>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE. */
+
+/**
+ * The two-sided stencil reference value fallback for r3xx-r4xx chips.
+ * These chips support two-sided stencil functions but they do not support
+ * a two-sided reference value.
+ *
+ * The functions below split every draw call which uses the two-sided
+ * reference value into two draw calls -- the first one renders front faces
+ * and the second renders back faces with the other reference value.
+ */
+
+#include "r300_context.h"
+#include "r300_reg.h"
+
+struct r300_stencilref_context {
+    void (*draw_vbo)(struct pipe_context *pipe,
+                     const struct pipe_draw_info *info);
+
+    uint32_t rs_cull_mode;
+    uint32_t zb_stencilrefmask;
+    ubyte ref_value_front;
+};
+
+static boolean r300_stencilref_needed(struct r300_context *r300)
+{
+    struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
+
+    return dsa->two_sided_stencil_ref ||
+           (dsa->two_sided &&
+            r300->stencil_ref.ref_value[0] != r300->stencil_ref.ref_value[1]);
+}
+
+/* Set drawing for front faces. */
+static void r300_stencilref_begin(struct r300_context *r300)
+{
+    struct r300_stencilref_context *sr = r300->stencilref_fallback;
+    struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
+    struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
+
+    /* Save state. */
+    sr->rs_cull_mode = rs->cb_main[rs->cull_mode_index];
+    sr->zb_stencilrefmask = dsa->stencil_ref_mask;
+    sr->ref_value_front = r300->stencil_ref.ref_value[0];
+
+    /* We *cull* pixels, therefore no need to mask out the bits. */
+    rs->cb_main[rs->cull_mode_index] |= R300_CULL_BACK;
+
+    r300->rs_state.dirty = TRUE;
+}
+
+/* Set drawing for back faces. */
+static void r300_stencilref_switch_side(struct r300_context *r300)
+{
+    struct r300_stencilref_context *sr = r300->stencilref_fallback;
+    struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
+    struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
+
+    rs->cb_main[rs->cull_mode_index] = sr->rs_cull_mode | R300_CULL_FRONT;
+    dsa->stencil_ref_mask = dsa->stencil_ref_bf;
+    r300->stencil_ref.ref_value[0] = r300->stencil_ref.ref_value[1];
+
+    r300->rs_state.dirty = TRUE;
+    r300->dsa_state.dirty = TRUE;
+}
+
+/* Restore the original state. */
+static void r300_stencilref_end(struct r300_context *r300)
+{
+    struct r300_stencilref_context *sr = r300->stencilref_fallback;
+    struct r300_rs_state *rs = (struct r300_rs_state*)r300->rs_state.state;
+    struct r300_dsa_state *dsa = (struct r300_dsa_state*)r300->dsa_state.state;
+
+    /* Restore state. */
+    rs->cb_main[rs->cull_mode_index] = sr->rs_cull_mode;
+    dsa->stencil_ref_mask = sr->zb_stencilrefmask;
+    r300->stencil_ref.ref_value[0] = sr->ref_value_front;
+
+    r300->rs_state.dirty = TRUE;
+    r300->dsa_state.dirty = TRUE;
+}
+
+static void r300_stencilref_draw_vbo(struct pipe_context *pipe,
+                                     const struct pipe_draw_info *info)
+{
+    struct r300_context *r300 = r300_context(pipe);
+    struct r300_stencilref_context *sr = r300->stencilref_fallback;
+
+    if (!r300_stencilref_needed(r300)) {
+        sr->draw_vbo(pipe, info);
+    } else {
+        r300_stencilref_begin(r300);
+        sr->draw_vbo(pipe, info);
+        r300_stencilref_switch_side(r300);
+        sr->draw_vbo(pipe, info);
+        r300_stencilref_end(r300);
+    }
+}
+
+void r300_plug_in_stencil_ref_fallback(struct r300_context *r300)
+{
+    r300->stencilref_fallback = CALLOC_STRUCT(r300_stencilref_context);
+
+    /* Save original draw function. */
+    r300->stencilref_fallback->draw_vbo = r300->context.draw_vbo;
+
+    /* Override the draw function. */
+    r300->context.draw_vbo = r300_stencilref_draw_vbo;
+}