/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License
 */

CCL_NAMESPACE_BEGIN

ccl_device void kernel_shader_evaluate(KernelGlobals *kg, ccl_global uint4 *input, ccl_global float4 *output, ShaderEvalType type, int i)
{
	ShaderData sd;
	uint4 in = input[i];
	float3 out;

	if(type == SHADER_EVAL_DISPLACE) {
		/* setup shader data */
		int object = in.x;
		int prim = in.y;
		float u = __uint_as_float(in.z);
		float v = __uint_as_float(in.w);

		shader_setup_from_displace(kg, &sd, object, prim, u, v);

		/* evaluate */
		float3 P = sd.P;
		shader_eval_displacement(kg, &sd, SHADER_CONTEXT_MAIN);
		out = sd.P - P;
	}
	else { // SHADER_EVAL_BACKGROUND
		/* setup ray */
		Ray ray;
		float u = __uint_as_float(in.x);
		float v = __uint_as_float(in.y);

		ray.P = make_float3(0.0f, 0.0f, 0.0f);
		ray.D = equirectangular_to_direction(u, v);
		ray.t = 0.0f;
#ifdef __CAMERA_MOTION__
		ray.time = 0.5f;
#endif

#ifdef __RAY_DIFFERENTIALS__
		ray.dD = differential3_zero();
		ray.dP = differential3_zero();
#endif

		/* setup shader data */
		shader_setup_from_background(kg, &sd, &ray, 0);

		/* evaluate */
		int flag = 0; /* we can't know which type of BSDF this is for */
		out = shader_eval_background(kg, &sd, flag, SHADER_CONTEXT_MAIN);
	}
	
	/* write output */
	output[i] = make_float4(out.x, out.y, out.z, 0.0f);
}

CCL_NAMESPACE_END