[PATCH v3 2/5] tests: Make ddx() and ddy() test behave correctly for shader models < 4.

[Francisco Casas]

From: Francisco Casas

---
 tests/ddxddy.shader_test | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/ddxddy.shader_test b/tests/ddxddy.shader_test
index 8becf524f..0dfdadbd0 100644
--- a/tests/ddxddy.shader_test
+++ b/tests/ddxddy.shader_test
@@ -1,16 +1,26 @@
+[require]
+shader model >= 3.0
+
 [pixel shader]
 float4 main(float4 pos : sv_position) : sv_target
 {
     return float4(ddx(pos.x), ddy(pos.y), 0, 0);
 }

+
 [test]
 draw quad
 probe all rgba (1.0, 1.0, 0.0, 0.0)

+
 [pixel shader]
 float4 main(float4 pos : sv_position) : sv_target
 {
+    // Shader models < 4 don't add 0.5 to sv_position, so this adjustment is required to get the
+    // same outputs.
+    pos.x = floor(pos.x) + 0.5;
+    pos.y = floor(pos.y) + 0.5;
+
     pos /= 10.0;
     float nonlinear = pos.x * pos.y - pos.x * (pos.x + 0.5);
     return float4(nonlinear, ddx(nonlinear), ddy(nonlinear), 0.0);