/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2016 by Mike Erwin.
 * All rights reserved.
 *
 * Contributor(s): Blender Foundation
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/gpu/GPU_shader_interface.h
 *  \ingroup gpu
 *
 * GPU shader interface (C --> GLSL)
 */

#ifndef __GPU_SHADER_INTERFACE_H__
#define __GPU_SHADER_INTERFACE_H__

#include "GPU_common.h"

typedef enum {
	GPU_UNIFORM_NONE = 0, /* uninitialized/unknown */

	GPU_UNIFORM_MODEL,      /* mat4 ModelMatrix */
	GPU_UNIFORM_VIEW,       /* mat4 ViewMatrix */
	GPU_UNIFORM_MODELVIEW,  /* mat4 ModelViewMatrix */
	GPU_UNIFORM_PROJECTION, /* mat4 ProjectionMatrix */
	GPU_UNIFORM_VIEWPROJECTION, /* mat4 ViewProjectionMatrix */
	GPU_UNIFORM_MVP,        /* mat4 ModelViewProjectionMatrix */

	GPU_UNIFORM_MODEL_INV,           /* mat4 ModelMatrixInverse */
	GPU_UNIFORM_VIEW_INV,            /* mat4 ViewMatrixInverse */
	GPU_UNIFORM_MODELVIEW_INV,       /* mat4 ModelViewMatrixInverse */
	GPU_UNIFORM_PROJECTION_INV,      /* mat4 ProjectionMatrixInverse */
	GPU_UNIFORM_VIEWPROJECTION_INV,  /* mat4 ViewProjectionMatrixInverse */

	GPU_UNIFORM_NORMAL,      /* mat3 NormalMatrix */
	GPU_UNIFORM_WORLDNORMAL, /* mat3 WorldNormalMatrix */
	GPU_UNIFORM_CAMERATEXCO, /* vec4 CameraTexCoFactors */
	GPU_UNIFORM_ORCO,        /* vec3 OrcoTexCoFactors[] */

	GPU_UNIFORM_COLOR, /* vec4 color */
	GPU_UNIFORM_EYE, /* vec3 eye */
	GPU_UNIFORM_CALLID, /* int callId */

	GPU_UNIFORM_CUSTOM, /* custom uniform, not one of the above built-ins */

	GPU_NUM_UNIFORMS, /* Special value, denotes number of builtin uniforms. */
} GPUUniformBuiltin;

typedef struct GPUShaderInput {
	struct GPUShaderInput *next;
	uint32_t name_offset;
	uint name_hash;
	GPUUniformBuiltin builtin_type; /* only for uniform inputs */
	uint32_t gl_type; /* only for attrib inputs */
	int32_t size; /* only for attrib inputs */
	int32_t location;
} GPUShaderInput;

#define GPU_NUM_SHADERINTERFACE_BUCKETS 257
#define GPU_SHADERINTERFACE_REF_ALLOC_COUNT 16

typedef struct GPUShaderInterface {
	int32_t program;
	uint32_t name_buffer_offset;
	GPUShaderInput *attrib_buckets[GPU_NUM_SHADERINTERFACE_BUCKETS];
	GPUShaderInput *uniform_buckets[GPU_NUM_SHADERINTERFACE_BUCKETS];
	GPUShaderInput *ubo_buckets[GPU_NUM_SHADERINTERFACE_BUCKETS];
	GPUShaderInput *builtin_uniforms[GPU_NUM_UNIFORMS];
	char *name_buffer;
	struct GPUBatch **batches; /* references to batches using this interface */
	uint batches_len;
} GPUShaderInterface;

GPUShaderInterface *GPU_shaderinterface_create(int32_t program_id);
void GPU_shaderinterface_discard(GPUShaderInterface *);

const GPUShaderInput *GPU_shaderinterface_uniform(const GPUShaderInterface *, const char *name);
const GPUShaderInput *GPU_shaderinterface_uniform_builtin(const GPUShaderInterface *, GPUUniformBuiltin);
const GPUShaderInput *GPU_shaderinterface_ubo(const GPUShaderInterface *, const char *name);
const GPUShaderInput *GPU_shaderinterface_attr(const GPUShaderInterface *, const char *name);

/* keep track of batches using this interface */
void GPU_shaderinterface_add_batch_ref(GPUShaderInterface *, struct GPUBatch *);
void GPU_shaderinterface_remove_batch_ref(GPUShaderInterface *, struct GPUBatch *);

#endif /* __GPU_SHADER_INTERFACE_H__ */