/*
 * Copyright 2012 Intel Corporation
 * Copyright 2015,2019 Collabora, Ltd.
 * Copyright 2016 NVIDIA Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "config.h"

#include <GLES2/gl2.h>

#include "gl-renderer.h"
#include "gl-renderer-internal.h"

/* static const char vertex_shader[]; vertex.glsl */
#include "vertex-shader.h"

/* Declare common fragment shader uniforms */
#define FRAGMENT_CONVERT_YUV						\
	"  y *= alpha;\n"						\
	"  u *= alpha;\n"						\
	"  v *= alpha;\n"						\
	"  gl_FragColor.r = y + 1.59602678 * v;\n"			\
	"  gl_FragColor.g = y - 0.39176229 * u - 0.81296764 * v;\n"	\
	"  gl_FragColor.b = y + 2.01723214 * u;\n"			\
	"  gl_FragColor.a = alpha;\n"

static const char fragment_debug[] =
	"  gl_FragColor = vec4(0.0, 0.3, 0.0, 0.2) + gl_FragColor * 0.8;\n";

static const char fragment_brace[] =
	"}\n";

static const char texture_fragment_shader_rgba[] =
	"precision mediump float;\n"
	"varying vec2 v_texcoord;\n"
	"uniform sampler2D tex;\n"
	"uniform float alpha;\n"
	"void main()\n"
	"{\n"
	"   gl_FragColor = alpha * texture2D(tex, v_texcoord)\n;"
	;

static const char texture_fragment_shader_rgbx[] =
	"precision mediump float;\n"
	"varying vec2 v_texcoord;\n"
	"uniform sampler2D tex;\n"
	"uniform float alpha;\n"
	"void main()\n"
	"{\n"
	"   gl_FragColor.rgb = alpha * texture2D(tex, v_texcoord).rgb\n;"
	"   gl_FragColor.a = alpha;\n"
	;

static const char texture_fragment_shader_egl_external[] =
	"#extension GL_OES_EGL_image_external : require\n"
	"precision mediump float;\n"
	"varying vec2 v_texcoord;\n"
	"uniform samplerExternalOES tex;\n"
	"uniform float alpha;\n"
	"void main()\n"
	"{\n"
	"   gl_FragColor = alpha * texture2D(tex, v_texcoord)\n;"
	;

static const char texture_fragment_shader_y_uv[] =
	"precision mediump float;\n"
	"uniform sampler2D tex;\n"
	"uniform sampler2D tex1;\n"
	"varying vec2 v_texcoord;\n"
	"uniform float alpha;\n"
	"void main() {\n"
	"  float y = 1.16438356 * (texture2D(tex, v_texcoord).x - 0.0625);\n"
	"  float u = texture2D(tex1, v_texcoord).r - 0.5;\n"
	"  float v = texture2D(tex1, v_texcoord).g - 0.5;\n"
	FRAGMENT_CONVERT_YUV
	;

static const char texture_fragment_shader_y_u_v[] =
	"precision mediump float;\n"
	"uniform sampler2D tex;\n"
	"uniform sampler2D tex1;\n"
	"uniform sampler2D tex2;\n"
	"varying vec2 v_texcoord;\n"
	"uniform float alpha;\n"
	"void main() {\n"
	"  float y = 1.16438356 * (texture2D(tex, v_texcoord).x - 0.0625);\n"
	"  float u = texture2D(tex1, v_texcoord).x - 0.5;\n"
	"  float v = texture2D(tex2, v_texcoord).x - 0.5;\n"
	FRAGMENT_CONVERT_YUV
	;

static const char texture_fragment_shader_y_xuxv[] =
	"precision mediump float;\n"
	"uniform sampler2D tex;\n"
	"uniform sampler2D tex1;\n"
	"varying vec2 v_texcoord;\n"
	"uniform float alpha;\n"
	"void main() {\n"
	"  float y = 1.16438356 * (texture2D(tex, v_texcoord).x - 0.0625);\n"
	"  float u = texture2D(tex1, v_texcoord).g - 0.5;\n"
	"  float v = texture2D(tex1, v_texcoord).a - 0.5;\n"
	FRAGMENT_CONVERT_YUV
	;

static const char texture_fragment_shader_xyuv[] =
	"precision mediump float;\n"
	"uniform sampler2D tex;\n"
	"varying vec2 v_texcoord;\n"
	"uniform float alpha;\n"
	"void main() {\n"
	"  float y = 1.16438356 * (texture2D(tex, v_texcoord).b - 0.0625);\n"
	"  float u = texture2D(tex, v_texcoord).g - 0.5;\n"
	"  float v = texture2D(tex, v_texcoord).r - 0.5;\n"
	FRAGMENT_CONVERT_YUV
	;

static const char solid_fragment_shader[] =
	"precision mediump float;\n"
	"uniform vec4 color;\n"
	"uniform float alpha;\n"
	"void main()\n"
	"{\n"
	"   gl_FragColor = alpha * color\n;"
	;

static int
compile_shader(GLenum type, int count, const char **sources)
{
	GLuint s;
	char msg[512];
	GLint status;

	s = glCreateShader(type);
	glShaderSource(s, count, sources, NULL);
	glCompileShader(s);
	glGetShaderiv(s, GL_COMPILE_STATUS, &status);
	if (!status) {
		glGetShaderInfoLog(s, sizeof msg, NULL, msg);
		weston_log("shader info: %s\n", msg);
		return GL_NONE;
	}

	return s;
}

int
shader_init(struct gl_shader *shader, struct gl_renderer *renderer,
		   const char *vertex_source, const char *fragment_source)
{
	char msg[512];
	GLint status;
	int count;
	const char *sources[3];

	shader->vertex_shader =
		compile_shader(GL_VERTEX_SHADER, 1, &vertex_source);
	if (shader->vertex_shader == GL_NONE)
		return -1;

	if (renderer->fragment_shader_debug) {
		sources[0] = fragment_source;
		sources[1] = fragment_debug;
		sources[2] = fragment_brace;
		count = 3;
	} else {
		sources[0] = fragment_source;
		sources[1] = fragment_brace;
		count = 2;
	}

	shader->fragment_shader =
		compile_shader(GL_FRAGMENT_SHADER, count, sources);
	if (shader->fragment_shader == GL_NONE)
		return -1;

	shader->program = glCreateProgram();
	glAttachShader(shader->program, shader->vertex_shader);
	glAttachShader(shader->program, shader->fragment_shader);
	glBindAttribLocation(shader->program, 0, "position");
	glBindAttribLocation(shader->program, 1, "texcoord");

	glLinkProgram(shader->program);
	glGetProgramiv(shader->program, GL_LINK_STATUS, &status);
	if (!status) {
		glGetProgramInfoLog(shader->program, sizeof msg, NULL, msg);
		weston_log("link info: %s\n", msg);
		return -1;
	}

	shader->proj_uniform = glGetUniformLocation(shader->program, "proj");
	shader->tex_uniforms[0] = glGetUniformLocation(shader->program, "tex");
	shader->tex_uniforms[1] = glGetUniformLocation(shader->program, "tex1");
	shader->tex_uniforms[2] = glGetUniformLocation(shader->program, "tex2");
	shader->alpha_uniform = glGetUniformLocation(shader->program, "alpha");
	shader->color_uniform = glGetUniformLocation(shader->program, "color");

	return 0;
}

void
shader_release(struct gl_shader *shader)
{
	glDeleteShader(shader->vertex_shader);
	glDeleteShader(shader->fragment_shader);
	glDeleteProgram(shader->program);

	shader->vertex_shader = 0;
	shader->fragment_shader = 0;
	shader->program = 0;
}

int
compile_shaders(struct weston_compositor *ec)
{
	struct gl_renderer *gr = get_renderer(ec);

	gr->texture_shader_rgba.vertex_source = vertex_shader;
	gr->texture_shader_rgba.fragment_source = texture_fragment_shader_rgba;

	gr->texture_shader_rgbx.vertex_source = vertex_shader;
	gr->texture_shader_rgbx.fragment_source = texture_fragment_shader_rgbx;

	gr->texture_shader_egl_external.vertex_source = vertex_shader;
	gr->texture_shader_egl_external.fragment_source =
		texture_fragment_shader_egl_external;

	gr->texture_shader_y_uv.vertex_source = vertex_shader;
	gr->texture_shader_y_uv.fragment_source = texture_fragment_shader_y_uv;

	gr->texture_shader_y_u_v.vertex_source = vertex_shader;
	gr->texture_shader_y_u_v.fragment_source =
		texture_fragment_shader_y_u_v;

	gr->texture_shader_y_xuxv.vertex_source = vertex_shader;
	gr->texture_shader_y_xuxv.fragment_source =
		texture_fragment_shader_y_xuxv;

	gr->texture_shader_xyuv.vertex_source = vertex_shader;
	gr->texture_shader_xyuv.fragment_source = texture_fragment_shader_xyuv;

	gr->solid_shader.vertex_source = vertex_shader;
	gr->solid_shader.fragment_source = solid_fragment_shader;

	return 0;
}