The previous formula for atan(x,y) returned a value of +/- pi whenever
|x|<0.0001, and used a formula based on atan(y/x) otherwise. This
broke in cases where both x and y were small (e.g. atan(1e-5, 1e-5)).
This patch modifies the formula so that it returns a value of +/- pi
whenever |x|<1e-8*|y|, and uses the formula based on atan(y/x)
otherwise.
---
src/glsl/builtins/ir/atan | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/src/glsl/builtins/ir/atan b/src/glsl/builtins/ir/atan
index cfecc1f..7b5ea13 100644
--- a/src/glsl/builtins/ir/atan
+++ b/src/glsl/builtins/ir/atan
@@ -54,7 +54,9 @@
)
(
(declare () float r)
- (if (expression bool > (expression float abs (var_ref x)) (constant
float (0.000100))) (
+ (if (expression bool >
+ (expression float abs (var_ref x))
+ (expression float * (constant float (1.0e-8)) (expression float abs
(var_ref y)))) (
(assign (x) (var_ref r) (call atan ((expression float / (var_ref y)
(var_ref x)))))
(if (expression bool < (var_ref x) (constant float (0.000000)) ) (
(if (expression bool >= (var_ref y) (constant float (0.000000)) )
--
1.7.6
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