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;;; Chickadee Game Toolkit
;;; Copyright © 2019 David Thompson <davet@gnu.org>
;;;
;;; Chickadee 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 3 of the License,
;;; or (at your option) any later version.
;;;
;;; Chickadee 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, see
;;; <http://www.gnu.org/licenses/>.
;;; Commentary:
;;
;; Simple forward rendered Phong lighting model.
;;
;;; Code:
(define-module (chickadee graphics phong)
#:use-module (chickadee math vector)
#:use-module (chickadee graphics)
#:use-module (chickadee graphics color)
#:use-module (chickadee graphics shader)
#:use-module (chickadee graphics texture)
#:use-module (srfi srfi-9)
#:export (make-phong-material
phong-material?
phong-material-name
phong-material-ambient
phong-material-ambient-map
phong-material-use-ambient-map?
phong-material-diffuse
phong-material-diffuse-map
phong-material-use-diffuse-map?
phong-material-specular
phong-material-specular-map?
phong-material-use-specular-map?
phong-material-specular-exponent
phong-material-bump-map
phong-material-use-bump-map?
default-phong-material
load-phong-shader
gpu-apply/phong))
;;;
;;; Phong Material
;;;
(define-shader-type <phong-material>
make-phong-material
phong-material?
(local-field name phong-material-name)
(float-vec3 ambient phong-material-ambient)
(local-field ambient-map phong-material-ambient-map)
(bool use-ambient-map phong-material-use-ambient-map?)
(float-vec3 diffuse phong-material-diffuse)
(local-field diffuse-map phong-material-diffuse-map)
(bool use-diffuse-map phong-material-use-diffuse-map?)
(float-vec3 specular phong-material-specular)
(local-field specular-map phong-material-specular-map)
(bool use-specular-map phong-material-use-specular-map?)
(float shininess phong-material-shininess)
(local-field bump-map phong-material-bump-map)
(bool use-bump-map phong-material-use-bump-map?))
(define default-phong-material
(make-phong-material #:name "default"
#:ambient (vec3 0.5 0.5 0.5)
#:ambient-map null-texture
#:use-ambient-map #f
#:diffuse (vec3 0.8 0.8 0.8)
#:diffuse-map null-texture
#:use-diffuse-map #f
#:specular (vec3 0.3 0.3 0.3)
#:specular-map null-texture
#:use-specular-map #f
#:shininess 32.0
#:bump-map null-texture
#:use-bump-map #f))
;;;
;;; Lights
;;;
(define-shader-type <directional-light>
make-directional-light
directional-light?
(float-vec3 direction directional-light-direction)
(float-vec3 ambient directional-light-ambient)
(float-vec3 diffuse directional-light-diffuse)
(float-vec3 specular directional-light-specular)
(float shininess directional-light-shininess))
(define default-directional-light
(make-directional-light #:direction (vec3 0.0 0.0 -1.0)
#:ambient (vec3 0.1 0.1 0.1)
#:diffuse (vec3 1.0 1.0 1.0)
#:specular (vec3 0.5 0.5 0.5)
#:shininess 32.0))
;;;
;;; Phong Shader
;;;
(define phong-shader
(delay
(strings->shader
"
#ifdef GLSL330
layout (location = 0) in vec3 position;
layout (location = 1) in vec2 texcoord;
layout (location = 2) in vec3 normal;
#elif defined(GLSL130)
in vec3 position;
in vec2 texcoord;
in vec3 normal;
#elif defined(GLSL120)
attribute vec3 position;
attribute vec2 texcoord;
attribute vec3 normal;
#endif
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
#ifdef GLSL120
varying vec3 fragNorm;
varying vec2 fragTex;
#else
out vec3 fragNorm;
out vec2 fragTex;
#endif
void main() {
gl_Position = projection * view * model * vec4(position, 1.0);
// TODO: Calculate normal matrix on CPU
fragNorm = normalize(model * vec4(normal, 1.0)).xyz;
fragTex = texcoord;
}
"
"
struct Material {
vec3 ambient;
sampler2D ambientMap;
bool useAmbientMap;
vec3 diffuse;
sampler2D diffuseMap;
bool useDiffuseMap;
vec3 specular;
sampler2D specularMap;
bool useSpecularMap;
float shininess;
sampler2D bumpMap;
bool useBumpMap;
};
struct DirectionalLight {
vec3 direction;
vec3 ambient;
vec3 diffuse;
vec3 specular;
};
#ifdef GLSL120
attribute vec3 fragNorm;
attribute vec2 fragTex;
#else
in vec3 fragNorm;
in vec2 fragTex;
#endif
#ifdef GLSL330
out vec4 fragColor;
#endif
uniform Material material;
uniform DirectionalLight directionalLight;
void main() {
vec3 baseAmbientColor;
vec3 baseDiffuseColor;
vec3 baseSpecularColor;
if(material.useAmbientMap) {
#ifdef GLSL330
baseAmbientColor = texture(material.ambientMap, fragTex).xyz;
#else
baseAmbientColor = texture2D(material.ambientMap, fragTex).xyz;
#endif
} else {
baseAmbientColor = vec3(1.0, 1.0, 1.0);
}
if(material.useDiffuseMap) {
// discard transparent fragments.
#ifdef GLSL330
vec4 color = texture(material.diffuseMap, fragTex);
#else
vec4 color = texture2D(material.diffuseMap, fragTex);
#endif
if(color.a == 0.0) { discard; }
baseDiffuseColor = color.xyz;
} else {
baseDiffuseColor = vec3(1.0, 1.0, 1.0);
}
if(material.useSpecularMap) {
#ifdef GLSL330
baseSpecularColor = texture(material.specularMap, fragTex).xyz;
#else
baseSpecularColor = texture2D(material.specularMap, fragTex).xyz;
#endif
} else {
baseSpecularColor = vec3(1.0, 1.0, 1.0);
}
vec3 ambientColor = material.ambient * baseAmbientColor * baseDiffuseColor;
vec3 lightDir = normalize(-directionalLight.direction);
float diffuseFactor = max(dot(lightDir, fragNorm), 0.0);
vec3 diffuseColor = diffuseFactor * baseDiffuseColor * material.diffuse;
vec3 reflectDir = reflect(-lightDir, fragNorm);
float specularFactor = 0;
if(material.shininess > 0) {
specularFactor = pow(max(dot(lightDir, reflectDir), 0.0), material.shininess);
}
vec3 specularColor = specularFactor * baseSpecularColor * material.specular;
#ifdef GLSL330
fragColor = vec4(ambientColor + diffuseColor + specularColor, 1.0);
#else
gl_FragColor = vec4(ambientColor + diffuseColor + specularColor, 1.0);
#endif
}
")))
(define (load-phong-shader)
(force phong-shader))
(define (gpu-apply/phong shader vertex-array material model-matrix view-matrix)
(with-texture 0 (phong-material-ambient-map material)
(with-texture 1 (phong-material-diffuse-map material)
(with-texture 2 (phong-material-specular-map material)
(with-texture 3 (phong-material-bump-map material)
(gpu-apply shader vertex-array
#:model model-matrix
#:view view-matrix
#:projection (current-projection)
#:material material
#:directional-light default-directional-light))))))
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