r300g: fix polygon offset

As per classic r300.

Not sure why glean/polygonOffset still fails, but we do emit the same register
values as in classic.

3 files changed, 54 insertions, 14 deletions

diff --git a/src/gallium/drivers/r300/r300_context.h b/src/gallium/drivers/r300/r300_context.h
index c65d23823c..5e33dc042a 100644
--- a/src/gallium/drivers/r300/r300_context.h
+++ b/src/gallium/drivers/r300/r300_context.h
@@ -87,10 +87,10 @@ struct r300_rs_state {
     uint32_t point_size;            /* R300_GA_POINT_SIZE: 0x421c */
     uint32_t point_minmax;          /* R300_GA_POINT_MINMAX: 0x4230 */
     uint32_t line_control;          /* R300_GA_LINE_CNTL: 0x4234 */
-    uint32_t depth_scale_front;  /* R300_SU_POLY_OFFSET_FRONT_SCALE: 0x42a4 */
-    uint32_t depth_offset_front;/* R300_SU_POLY_OFFSET_FRONT_OFFSET: 0x42a8 */
-    uint32_t depth_scale_back;    /* R300_SU_POLY_OFFSET_BACK_SCALE: 0x42ac */
-    uint32_t depth_offset_back;  /* R300_SU_POLY_OFFSET_BACK_OFFSET: 0x42b0 */
+    float depth_scale;            /* R300_SU_POLY_OFFSET_FRONT_SCALE: 0x42a4 */
+                                  /* R300_SU_POLY_OFFSET_BACK_SCALE: 0x42ac */
+    float depth_offset;           /* R300_SU_POLY_OFFSET_FRONT_OFFSET: 0x42a8 */
+                                  /* R300_SU_POLY_OFFSET_BACK_OFFSET: 0x42b0 */
     uint32_t polygon_offset_enable; /* R300_SU_POLY_OFFSET_ENABLE: 0x42b4 */
     uint32_t cull_mode;             /* R300_SU_CULL_MODE: 0x42b8 */
     uint32_t line_stipple_config;   /* R300_GA_LINE_STIPPLE_CONFIG: 0x4328 */
@@ -326,6 +326,10 @@ struct r300_context {
     uint32_t dirty_hw;
     /* Whether the TCL engine should be in bypass mode. */
     boolean tcl_bypass;
+    /* Whether polygon offset is enabled. */
+    boolean polygon_offset_enabled;
+    /* Z buffer bit depth. */
+    uint32_t zbuffer_bpp;
 };
 
 /* Convenience cast wrapper. */
diff --git a/src/gallium/drivers/r300/r300_emit.c b/src/gallium/drivers/r300/r300_emit.c
index 11bd3346c7..2ea9fab015 100644
--- a/src/gallium/drivers/r300/r300_emit.c
+++ b/src/gallium/drivers/r300/r300_emit.c
@@ -584,19 +584,37 @@ void r300_emit_query_end(struct r300_context* r300)
 void r300_emit_rs_state(struct r300_context* r300, void* state)
 {
     struct r300_rs_state* rs = (struct r300_rs_state*)state;
+    float scale, offset;
     CS_LOCALS(r300);
 
-    BEGIN_CS(22);
+    BEGIN_CS(18 + (rs->polygon_offset_enable ? 5 : 0));
     OUT_CS_REG(R300_VAP_CNTL_STATUS, rs->vap_control_status);
     OUT_CS_REG(R300_GA_POINT_SIZE, rs->point_size);
     OUT_CS_REG_SEQ(R300_GA_POINT_MINMAX, 2);
     OUT_CS(rs->point_minmax);
     OUT_CS(rs->line_control);
-    OUT_CS_REG_SEQ(R300_SU_POLY_OFFSET_FRONT_SCALE, 6);
-    OUT_CS(rs->depth_scale_front);
-    OUT_CS(rs->depth_offset_front);
-    OUT_CS(rs->depth_scale_back);
-    OUT_CS(rs->depth_offset_back);
+
+    if (rs->polygon_offset_enable) {
+        scale = rs->depth_scale * 12;
+        offset = rs->depth_offset;
+
+        switch (r300->zbuffer_bpp) {
+            case 16:
+                offset *= 4;
+                break;
+            case 24:
+                offset *= 2;
+                break;
+        }
+
+        OUT_CS_REG_SEQ(R300_SU_POLY_OFFSET_FRONT_SCALE, 4);
+        OUT_CS_32F(scale);
+        OUT_CS_32F(offset);
+        OUT_CS_32F(scale);
+        OUT_CS_32F(offset);
+    }
+
+    OUT_CS_REG_SEQ(R300_SU_POLY_OFFSET_ENABLE, 2);
     OUT_CS(rs->polygon_offset_enable);
     OUT_CS(rs->cull_mode);
     OUT_CS_REG(R300_GA_LINE_STIPPLE_CONFIG, rs->line_stipple_config);
diff --git a/src/gallium/drivers/r300/r300_state.c b/src/gallium/drivers/r300/r300_state.c
index 609b910e12..e2ec0bc5bd 100644
--- a/src/gallium/drivers/r300/r300_state.c
+++ b/src/gallium/drivers/r300/r300_state.c
@@ -486,6 +486,7 @@ static void
                                const struct pipe_framebuffer_state* state)
 {
     struct r300_context* r300 = r300_context(pipe);
+    uint32_t zbuffer_bpp = 0;
 
     if (r300->draw) {
         draw_flush(r300->draw);
@@ -499,6 +500,23 @@ static void
     r300->blend_state.dirty = TRUE;
     r300->dsa_state.dirty = TRUE;
     r300->scissor_state.dirty = TRUE;
+
+    /* Polyfon offset depends on the zbuffer bit depth. */
+    if (state->zsbuf && r300->polygon_offset_enabled) {
+        switch (util_format_get_blocksize(state->zsbuf->texture->format)) {
+            case 2:
+                zbuffer_bpp = 16;
+                break;
+            case 4:
+                zbuffer_bpp = 24;
+                break;
+        }
+
+        if (r300->zbuffer_bpp != zbuffer_bpp) {
+            r300->zbuffer_bpp = zbuffer_bpp;
+            r300->rs_state.dirty = TRUE;
+        }
+    }
 }
 
 /* Create fragment shader state. */
@@ -654,10 +672,8 @@ static void* r300_create_rs_state(struct pipe_context* pipe,
     }
 
     if (rs->polygon_offset_enable) {
-        rs->depth_offset_front = rs->depth_offset_back =
-            fui(state->offset_units);
-        rs->depth_scale_front = rs->depth_scale_back =
-            fui(state->offset_scale);
+        rs->depth_offset = state->offset_units;
+        rs->depth_scale = state->offset_scale;
     }
 
     if (state->line_stipple_enable) {
@@ -691,8 +707,10 @@ static void r300_bind_rs_state(struct pipe_context* pipe, void* state)
 
     if (rs) {
         r300->tcl_bypass = rs->rs.bypass_vs_clip_and_viewport;
+        r300->polygon_offset_enabled = rs->rs.offset_cw || rs->rs.offset_ccw;
     } else {
         r300->tcl_bypass = FALSE;
+        r300->polygon_offset_enabled = FALSE;
     }
 
     r300->rs_state.state = rs;