exponentop implements gpu path

src/core/ExponentOps.cpp

@@ -26,15 +26,16 @@ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+#include <cmath>
+#include <cstring>
+#include <sstream>
+
 #include <OpenColorIO/OpenColorIO.h>
 
+#include "GpuShaderUtils.h"
 #include "MatrixOps.h"
 #include "MathUtils.h"
 
-#include <cmath>
-#include <cstring>
-#include <sstream>
-
 OCIO_NAMESPACE_ENTER
 {
     namespace
@@ -171,15 +172,19 @@ OCIO_NAMESPACE_ENTER
 
         bool ExponentOp::supportsGpuShader() const
         {
-            return false;
+            return true;
         }
 
-        void ExponentOp::writeGpuShader(std::ostringstream & /*shader*/,
-                                        const std::string & /*pixelName*/,
-                                        const GpuShaderDesc & /*shaderDesc*/) const
+        void ExponentOp::writeGpuShader(std::ostringstream & shader,
+                                        const std::string & pixelName,
+                                        const GpuShaderDesc & shaderDesc) const
         {
-            // TODO: Add Gpu Shader for exponent op
-            throw Exception("ExponentOp does not support analytical shader generation.");
+            GpuLanguage lang = shaderDesc.getLanguage();
+            float zerovec[4] = { 0.0f, 0.0f, 0.0f, 0.0f };
+
+            shader << pixelName << " = pow(";
+            shader << "max(" << pixelName << ", " << GpuTextHalf4(zerovec, lang) << ")";
+            shader << ", " << GpuTextHalf4(m_finalExp4, lang) << ");\n";
         }
 
         bool ExponentOp::definesGpuAllocation() const