Cycles: support for camera rendering an environment map with equirectangular

environment map, by enabling the Panorama option in the camera.

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Camera#Panorama

The focal length or sensor settings are not used, the UI can be tweaked still to
communicate this, also panorama should probably become a proper camera type like
perspective or ortho.

5 files changed, 61 insertions, 16 deletions

diff --git a/intern/cycles/kernel/kernel_camera.h b/intern/cycles/kernel/kernel_camera.h
index 2dbdd076891..251b2c280da 100644
--- a/intern/cycles/kernel/kernel_camera.h
+++ b/intern/cycles/kernel/kernel_camera.h
@@ -122,6 +122,44 @@ __device void camera_sample_orthographic(KernelGlobals *kg, float raster_x, floa
 #endif
 }
 
+/* Environment Camera */
+
+__device void camera_sample_environment(KernelGlobals *kg, float raster_x, float raster_y, Ray *ray)
+{
+	Transform rastertocamera = kernel_data.cam.rastertocamera;
+	float3 Pcamera = transform(&rastertocamera, make_float3(raster_x, raster_y, 0.0f));
+
+	/* create ray form raster position */
+	ray->P = make_float3(0.0, 0.0f, 0.0f);
+	ray->D = equirectangular_to_direction(Pcamera.x, Pcamera.y);
+
+	/* transform ray from camera to world */
+	Transform cameratoworld = kernel_data.cam.cameratoworld;
+
+	ray->P = transform(&cameratoworld, ray->P);
+	ray->D = transform_direction(&cameratoworld, ray->D);
+	ray->D = normalize(ray->D);
+
+#ifdef __RAY_DIFFERENTIALS__
+	/* ray differential */
+	ray->dP.dx = make_float3(0.0f, 0.0f, 0.0f);
+	ray->dP.dy = make_float3(0.0f, 0.0f, 0.0f);
+
+	Pcamera = transform(&rastertocamera, make_float3(raster_x + 1.0f, raster_y, 0.0f));
+	ray->dD.dx = equirectangular_to_direction(Pcamera.x, Pcamera.y) - ray->D;
+
+	Pcamera = transform(&rastertocamera, make_float3(raster_x, raster_y + 1.0f, 0.0f));
+	ray->dD.dy = equirectangular_to_direction(Pcamera.x, Pcamera.y) - ray->D;
+#endif
+
+#ifdef __CAMERA_CLIPPING__
+	/* clipping */
+	ray->t = kernel_data.cam.cliplength;
+#else
+	ray->t = FLT_MAX;
+#endif
+}
+
 /* Common */
 
 __device void camera_sample(KernelGlobals *kg, int x, int y, float filter_u, float filter_v, float lens_u, float lens_v, Ray *ray)
@@ -134,10 +172,12 @@ __device void camera_sample(KernelGlobals *kg, int x, int y, float filter_u, flo
 	//ray->time = lerp(time_t, kernel_data.cam.shutter_open, kernel_data.cam.shutter_close);
 
 	/* sample */
-	if(kernel_data.cam.ortho)
+	if(kernel_data.cam.type == CAMERA_PERSPECTIVE)
+		camera_sample_perspective(kg, raster_x, raster_y, lens_u, lens_v, ray);
+	else if(kernel_data.cam.type == CAMERA_ORTHOGRAPHIC)
 		camera_sample_orthographic(kg, raster_x, raster_y, ray);
 	else
-		camera_sample_perspective(kg, raster_x, raster_y, lens_u, lens_v, ray);
+		camera_sample_environment(kg, raster_x, raster_y, ray);
 }
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/kernel/kernel_displace.h b/intern/cycles/kernel/kernel_displace.h
index 73666892cf3..f4b33605f5b 100644
--- a/intern/cycles/kernel/kernel_displace.h
+++ b/intern/cycles/kernel/kernel_displace.h
@@ -41,9 +41,11 @@ __device void kernel_shader_evaluate(KernelGlobals *kg, uint4 *input, float4 *ou
 	else { // SHADER_EVAL_BACKGROUND
 		/* setup ray */
 		Ray ray;
+		float u = __int_as_float(in.x);
+		float v = __int_as_float(in.y);
 
 		ray.P = make_float3(0.0f, 0.0f, 0.0f);
-		ray.D = make_float3(__int_as_float(in.x), __int_as_float(in.y), __int_as_float(in.z));
+		ray.D = equirectangular_to_direction(u, v);
 		ray.t = 0.0f;
 
 #ifdef __RAY_DIFFERENTIALS__
diff --git a/intern/cycles/kernel/kernel_light.h b/intern/cycles/kernel/kernel_light.h
index aa125180a94..42260577069 100644
--- a/intern/cycles/kernel/kernel_light.h
+++ b/intern/cycles/kernel/kernel_light.h
@@ -120,13 +120,9 @@ __device float3 background_light_sample(KernelGlobals *kg, float randu, float ra
 	float du = (randu - cdf_u.y) / (cdf_next_u.y - cdf_u.y);
 	float u = (index_u + du) / res;
 
-	/* spherical coordinates */
-	float theta = v * M_PI_F;
-	float phi = u * M_PI_F * 2.0f;
-
 	/* compute pdf */
 	float denom = cdf_last_u.x * cdf_last_v.x;
-	float sin_theta = sinf(theta);
+	float sin_theta = sinf(M_PI_F * v);
 
 	if(sin_theta == 0.0f || denom == 0.0f)
 		*pdf = 0.0f;
@@ -136,7 +132,7 @@ __device float3 background_light_sample(KernelGlobals *kg, float randu, float ra
 	*pdf *= kernel_data.integrator.pdf_lights;
 
 	/* compute direction */
-	return spherical_to_direction(theta, phi);
+	return -equirectangular_to_direction(u, v);
 }
 
 __device float background_light_pdf(KernelGlobals *kg, float3 direction)
diff --git a/intern/cycles/kernel/kernel_montecarlo.h b/intern/cycles/kernel/kernel_montecarlo.h
index 9776baf65e4..66bd0ee9998 100644
--- a/intern/cycles/kernel/kernel_montecarlo.h
+++ b/intern/cycles/kernel/kernel_montecarlo.h
@@ -185,7 +185,7 @@ __device float2 regular_polygon_sample(float corners, float rotation, float u, f
 	return make_float2(cr*p.x - sr*p.y, sr*p.x + cr*p.y);
 }
 
-/* Spherical coordinates <-> Cartesion direction  */
+/* Spherical coordinates <-> Cartesian direction  */
 
 __device float2 direction_to_spherical(float3 dir)
 {
@@ -203,11 +203,11 @@ __device float3 spherical_to_direction(float theta, float phi)
 		cosf(theta));
 }
 
-/* Equirectangular */
+/* Equirectangular coordinates <-> Cartesian direction */
 
 __device float2 direction_to_equirectangular(float3 dir)
 {
-	float u = (atan2f(dir.y, dir.x) + M_PI_F)/(2.0f*M_PI_F);
+	float u = -atan2f(dir.y, dir.x)/(2.0f*M_PI_F) + 0.5f;
 	float v = atan2f(dir.z, hypotf(dir.x, dir.y))/M_PI_F + 0.5f;
 
 	return make_float2(u, v);
@@ -215,9 +215,8 @@ __device float2 direction_to_equirectangular(float3 dir)
 
 __device float3 equirectangular_to_direction(float u, float v)
 {
-	/* XXX check correctness? */
-	float theta = M_PI_F*v;
-	float phi = 2.0f*M_PI_F*u;
+	float phi = M_PI_F*(1.0f - 2.0f*u);
+	float theta = M_PI_F*(1.0f - v);
 
 	return make_float3(
 		sin(theta)*cos(phi),
diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index 9f4d5b00e2c..61335d5f9fa 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -240,6 +240,14 @@ typedef enum LightType {
 	LIGHT_AREA
 } LightType;
 
+/* Camera Type */
+
+enum CameraType {
+	CAMERA_PERSPECTIVE,
+	CAMERA_ORTHOGRAPHIC,
+	CAMERA_ENVIRONMENT
+};
+
 /* Differential */
 
 typedef struct differential3 {
@@ -387,7 +395,7 @@ typedef struct ShaderData {
 
 typedef struct KernelCamera {
 	/* type */
-	int ortho;
+	int type;
 	int pad1, pad2, pad3;
 
 	/* matrices */