Implementation of curve mapping in GLSL

The title says it all, now having curve mapping
enabled in color management settings wouldn't
force fallback from GLSL to CPU based color space
conversion.

1 files changed, 58 insertions, 1 deletions

diff --git a/intern/opencolorio/ocio_capi.h b/intern/opencolorio/ocio_capi.h
index 0846b8ff7b3..5532ade1f3a 100644
--- a/intern/opencolorio/ocio_capi.h
+++ b/intern/opencolorio/ocio_capi.h
@@ -54,6 +54,62 @@ OCIO_DECLARE_HANDLE(OCIO_ExponentTransformRcPtr);
 OCIO_DECLARE_HANDLE(OCIO_MatrixTransformRcPtr);
 OCIO_DECLARE_HANDLE(OCIO_ConstLookRcPtr);
 
+/* This structure is used to pass curve mapping settings from
+ * blender's DNA structure stored in view transform settings
+ * to a generic OpenColorIO C-API.
+ */
+typedef struct OCIO_CurveMappingSettings {
+	/* This is a LUT which contain values for all 4 curve mapping tables
+	 * (combined, R, G and B).
+	 *
+	 * Element I for table T is stored at I * 4 + T element of this LUT.
+	 *
+	 * This array is usually returned by curvemapping_table_RGBA().
+	 */
+	float *lut;
+
+	/* Size of single curve mapping table, 1/4 size of lut array. */
+	int lut_size;
+
+	/* Extend extrapolation flags for all the tables.
+	 * if use_extend_extrapolate[T] != 0 means extrapolation for
+	 * table T is needed.
+	 */
+	int use_extend_extrapolate[4];
+
+	/* Minimal X value of the curve mapping tables. */
+	float mintable[4];
+
+	/* Per curve mapping table range. */
+	float range[4];
+
+	/* Lower extension value, stored as per-component arrays. */
+	float ext_in_x[4], ext_in_y[4];
+
+	/* Higher extension value, stored as per-component arrays. */
+	float ext_out_x[4], ext_out_y[4];
+
+	/* First points of the tables, both X and Y values.
+	 * Needed for easier and faster access when extrapolating.
+	 */
+	float first_x[4], first_y[4];
+
+	/* Last points of the tables, both X and Y values.
+	 * Needed for easier and faster access when extrapolating.
+	 */
+	float last_x[4], last_y[4];
+
+	/* Premultiplication settings: black level and scale to match
+	 * with white level.
+	 */
+	float black[3], bwmul[3];
+
+	/* Cache id of the original curve mapping, used to detect when
+	 * upload of new settings to GPU is needed.
+	 */
+	size_t cache_id;
+} OCIO_CurveMappingSettings;
+
 void OCIO_init(void);
 void OCIO_exit(void);
 
@@ -132,7 +188,8 @@ void OCIO_matrixTransformRelease(OCIO_MatrixTransformRcPtr *mt);
 void OCIO_matrixTransformScale(float *m44, float *offset4, const float *scale4);
 
 int OCIO_supportGLSLDraw(void);
-int OCIO_setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor, int predivide);
+int OCIO_setupGLSLDraw(struct OCIO_GLSLDrawState **state_r, OCIO_ConstProcessorRcPtr *processor,
+                       OCIO_CurveMappingSettings *curve_mapping_settings, bool predivide);
 void OCIO_finishGLSLDraw(struct OCIO_GLSLDrawState *state);
 void OCIO_freeOGLState(struct OCIO_GLSLDrawState *state);