//LoadPng tries to load a png file from hard drive and upload it to the GPU.
func LoadPng(file string) (gl2.Texture2D, error) {
imgFile, err := os.Open(file)
if err != nil {
return 0, nil
}
defer imgFile.Close()
img, _, err := image.Decode(imgFile)
if err != nil {
return 0, nil
}
rgba := image.NewRGBA(img.Bounds())
if rgba.Stride != rgba.Rect.Size().X*4 {
return 0, fmt.Errorf("unsupported stride")
}
draw.Draw(rgba, rgba.Bounds(), img, image.Point{0, 0}, draw.Src)
texture := gl2.GenTexture2D()
gl.ActiveTexture(gl2.TEXTURE0)
texture.Bind()
defer texture.Unbind()
texture.MinFilter(gl2.LINEAR)
texture.MagFilter(gl2.LINEAR)
texture.WrapS(gl2.CLAMP_TO_EDGE)
texture.WrapT(gl2.CLAMP_TO_EDGE)
texture.TexImage2D(0, gl2.RGBA, int32(rgba.Rect.Size().X), int32(rgba.Rect.Size().Y), 0, gl2.RGBA, gl2.UNSIGNED_BYTE, gl.Ptr(rgba.Pix))
return texture, nil
}
//GenRGBTexture2D is a utility function to generate an empty 2D textures of size (width,height), internal format RGB adn data type UNSIGNED_BYTE
func GenRGBTexture2D(width, height int32) gl.Texture2D {
tex := gl.GenTexture2D()
tex.Bind()
tex.MinFilter(gl.LINEAR)
tex.MagFilter(gl.LINEAR)
tex.WrapS(gl.CLAMP_TO_EDGE)
tex.WrapT(gl.CLAMP_TO_EDGE)
tex.TexImage2D(0, gl.RGB, width, height, 0, gl.RGB, gl.UNSIGNED_BYTE, nil)
return tex
}
//GenDepthTexture is a utility function to generate a depth Texture2D
func GenDepthTexture(width, height int32) gl2.Texture2D {
tex := gl2.GenTexture2D()
tex.Bind()
defer tex.Unbind()
tex.MinFilter(gl2.NEAREST)
tex.MagFilter(gl2.NEAREST)
tex.WrapS(gl2.CLAMP_TO_EDGE)
tex.WrapT(gl2.CLAMP_TO_EDGE)
tex.TexImage2D(0, gl.DEPTH_COMPONENT, width, height, 0, gl.DEPTH_COMPONENT, gl.FLOAT, nil)
return tex
}
//NewShadowFBO will create a new FBO, a new depth texture and the program needed to generate shadow map
//currently not optimized, we should probably reuse the FBO and absolutely reuse the program.
func NewShadowFBO(width, height int32) (*ShadowFBO, error) {
sfbo := ShadowFBO{}
fbo := gl2.GenFramebuffer()
sfbo.width, sfbo.height = width, height
sfbo.framebuffer = fbo
fbo.Bind(gl2.FRAMEBUFFER)
defer fbo.Unbind(gl2.FRAMEBUFFER)
shadowtex := gl2.GenTexture2D()
sfbo.texture = shadowtex
shadowtex.Bind()
defer shadowtex.Unbind()
shadowtex.TexParameteriv(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
shadowtex.TexParameteriv(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
shadowtex.TexParameteriv(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
shadowtex.TexParameteriv(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
shadowtex.TexParameteriv(gl.TEXTURE_2D, gl.TEXTURE_COMPARE_MODE, gl.COMPARE_REF_TO_TEXTURE)
shadowtex.TexParameteriv(gl.TEXTURE_2D, gl.TEXTURE_COMPARE_FUNC, gl.LEQUAL)
shadowtex.TexImage2D(0, gl.DEPTH_COMPONENT16, width, height, 0, gl.DEPTH_COMPONENT, gl.FLOAT, nil)
fbo.Texture(gl2.FRAMEBUFFER, gl2.DEPTH_ATTACHMENT, shadowtex, 0 /*level*/)
fbo.DrawBuffer(gl2.NONE)
fbo.ReadBuffer(gl2.NONE)
if gl.CheckFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE {
return &sfbo, errors.New("framebuffer incomplete")
}
vs, err := CompileShader(_shadowFboVertexShader, gl2.VERTEX_SHADER)
if err != nil {
return &sfbo, err
}
defer vs.Delete()
fs, err := CompileShader(_shadowFboFragmentShader, gl2.FRAGMENT_SHADER)
if err != nil {
return &sfbo, err
}
defer fs.Delete()
prog, err := NewProgram(vs, fs)
if err != nil {
return &sfbo, err
}
sfbo.program = prog
prog.Use()
sfbo.mvpUni = prog.GetUniformLocation("mvp")
return &sfbo, nil
}
//NewGBuffer will create a new geometry buffer and allocate all the resources required
func NewGBuffer(width, height int32) (gbuffer GBuffer, err error) {
const (
_gbufferVertexShaderSource = `#version 330
uniform mat4 M;
uniform mat4 MVP;
layout (location=0) in vec3 vert;
layout (location=1) in vec2 vertTexCoord;
layout (location=2) in vec3 vertNormal;
out vec2 fragTexCoord;
out vec3 normal;
out vec3 world_pos;
void main() {
normal = vertNormal;
fragTexCoord = vertTexCoord;
world_pos=(M*vec4(vert,1)).xyz;
gl_Position = MVP * vec4(vert, 1);
}
` + "\x00"
_gbufferFragmentShaderSource = `#version 330
uniform sampler2D diffuse;
uniform mat4 N;
in vec2 fragTexCoord;
in vec3 normal;
in vec3 world_pos;
layout (location=0) out vec3 outColor;
layout (location=1) out vec3 outNormal;
layout (location=2) out vec3 outPosition;
void main() {
outColor = texture(diffuse, fragTexCoord).rgb;
outNormal = (N*vec4(normal,1)).xyz;
outPosition = world_pos;
}
` + "\x00"
//shouldnt be there
_gbufferAggregateFragmentShader = `#version 330
#define MAX_POINT_LIGHT 8
#define MIN_LUX 0.3
//GBuffer textures
uniform sampler2D diffusetex;
uniform sampler2D normaltex;
uniform sampler2D postex;
uniform sampler2D depthtex;
//cook
uniform float roughnessValue;
uniform float F0;
uniform float k;
//Lights
uniform int NUM_POINT_LIGHT;
uniform vec3 point_light_pos[MAX_POINT_LIGHT];
uniform vec3 point_light_color[MAX_POINT_LIGHT];
//Shadows
uniform sampler2DShadow shadowmap;
uniform mat4 shadowmat;
//View
uniform vec3 cam_pos;
in vec2 uv;
layout (location=0) out vec4 outColor;
void main(){
vec3 normal = normalize(texture(normaltex, uv).xyz);
vec3 world_position = texture(postex, uv).xyz;
vec4 shadowcoord = shadowmat*vec4(world_position, 1);
shadowcoord.z+=0.005;
float shadow = texture(shadowmap, shadowcoord.xyz,0);
//////cook torrance
//material values
vec3 lightColor = vec3(0.9,0.1,0.1);
vec3 world_pos = texture(postex, uv).xyz;
vec3 lightDir = point_light_pos[0]-world_pos;
float NdL = max(dot(normal, lightDir), 0);
float lux = shadow;
if(shadow > 0){
float specular = 0.0;
if(NdL > 0.0){
vec3 eyeDir = normalize(cam_pos-world_pos);
vec3 halfVec = normalize(lightDir+eyeDir);
float NdH = max(0,dot(normal,halfVec));
float NdV = max(0,dot(normal, eyeDir));
float VdH = max(0,dot(eyeDir, halfVec));
float mSqu = roughnessValue*roughnessValue;
float NH2 = 2.0*NdH;
float geoAtt = min(1.0,min((NH2*NdV)/VdH,(NH2*NdL)/VdH));
float roughness = (1.0 / ( 4.0 * mSqu * pow(NdH, 4.0)))*exp((NdH * NdH - 1.0) / (mSqu * NdH * NdH));
float fresnel = pow(1.0 - VdH, 5.0)*(1.0 - F0)+F0;
specular = (fresnel*geoAtt*roughness)/(NdV*NdL*3.14);
}
lux=NdL * (k + specular * (1.0 - k));
}
if(lux < MIN_LUX){
lux=MIN_LUX;
}
outColor = texture(diffusetex, uv)*lux;
}
` + "\x00"
)
gbuffer.width, gbuffer.height = width, height
fb := gl2.GenFramebuffer()
fb.Bind(gl2.FRAMEBUFFER)
defer fb.Unbind(gl2.FRAMEBUFFER)
gbuffer.framebuffer = fb
depthtex := gl2.GenTexture2D()
depthtex.Bind()
depthtex.MinFilter(gl2.NEAREST)
depthtex.MagFilter(gl2.NEAREST)
depthtex.WrapS(gl2.CLAMP_TO_EDGE)
depthtex.WrapT(gl2.CLAMP_TO_EDGE)
depthtex.TexImage2D(0, gl2.DEPTH24_STENCIL8, width, height, 0, gl2.DEPTH_STENCIL, gl2.UNSIGNED_INT_24_8, nil)
diffuseTex := gl2.GenTexture2D()
diffuseTex.Bind()
diffuseTex.MinFilter(gl2.LINEAR)
diffuseTex.MagFilter(gl2.LINEAR)
diffuseTex.WrapS(gl2.CLAMP_TO_EDGE)
diffuseTex.WrapT(gl2.CLAMP_TO_EDGE)
diffuseTex.TexImage2D(0, gl2.RGB16F, width, height, 0, gl2.RGBA, gl2.FLOAT, nil)
normalTex := gl2.GenTexture2D()
normalTex.Bind()
normalTex.MinFilter(gl2.LINEAR)
normalTex.MagFilter(gl2.LINEAR)
normalTex.WrapS(gl2.CLAMP_TO_EDGE)
normalTex.WrapT(gl2.CLAMP_TO_EDGE)
normalTex.TexImage2D(0, gl2.RGB16F, width, height, 0, gl2.RGB, gl2.FLOAT, nil)
positionTex := gl2.GenTexture2D()
positionTex.Bind()
positionTex.MinFilter(gl2.LINEAR)
positionTex.MagFilter(gl2.LINEAR)
positionTex.WrapS(gl2.CLAMP_TO_EDGE)
positionTex.WrapT(gl2.CLAMP_TO_EDGE)
positionTex.TexImage2D(0, gl2.RGB16F, width, height, 0, gl2.RGB, gl2.FLOAT, nil)
fb.DrawBuffers(gl2.COLOR_ATTACHMENT0, gl2.COLOR_ATTACHMENT1, gl2.COLOR_ATTACHMENT2)
fb.Texture(gl2.FRAMEBUFFER, gl2.COLOR_ATTACHMENT0, diffuseTex, 0 /*level*/)
fb.Texture(gl2.FRAMEBUFFER, gl2.COLOR_ATTACHMENT1, normalTex, 0 /*level*/)
fb.Texture(gl2.FRAMEBUFFER, gl2.COLOR_ATTACHMENT2, positionTex, 0 /*level*/)
fb.Texture(gl2.FRAMEBUFFER, gl2.DEPTH_STENCIL_ATTACHMENT, depthtex, 0 /*level*/)
gbuffer.DiffuseTex = diffuseTex
gbuffer.NormalTex = normalTex
gbuffer.PositionTex = positionTex
gbuffer.DepthTex = depthtex
vs, err := CompileShader(_gbufferVertexShaderSource, gl2.VERTEX_SHADER)
if err != nil {
return
}
fs, err := CompileShader(_gbufferFragmentShaderSource, gl2.FRAGMENT_SHADER)
if err != nil {
return
}
prog, err := NewProgram(vs, fs)
if err != nil {
return
}
gbuffer.program = prog
prog.Use()
defer prog.Unuse()
gbuffer.PUni = prog.GetUniformLocation("P")
gbuffer.VUni = prog.GetUniformLocation("V")
gbuffer.MUni = prog.GetUniformLocation("M")
gbuffer.NUni = prog.GetUniformLocation("N")
gbuffer.MVPUni = prog.GetUniformLocation("MVP")
gbuffer.DiffuseUni = prog.GetUniformLocation("diffuse")
//shadow map
prog.BindFragDataLocation(0, "")
prog.BindFragDataLocation(1, "")
prog.BindFragDataLocation(2, "")
//Aggregated fb and textures, essentially a special post process effect
aggfb := AggregateFB{}
gbuffer.AggregateFramebuffer = aggfb
avs, err := CompileShader(_fullscreenVertexShader, gl2.VERTEX_SHADER)
if err != nil {
return
}
afs, err := CompileShader(_gbufferAggregateFragmentShader, gl2.FRAGMENT_SHADER)
if err != nil {
return
}
aprog, err := NewProgram(avs, afs)
if err != nil {
return
}
aggfb.program = aprog
aggfb.framebuffer = gl2.GenFramebuffer()
aggfb.framebuffer.Bind(gl2.FRAMEBUFFER)
aggfb.Out = gl2.GenTexture2D()
aggfb.Out.Bind()
aggfb.Out.MinFilter(gl2.LINEAR)
aggfb.Out.MagFilter(gl2.LINEAR)
aggfb.Out.WrapS(gl2.CLAMP_TO_EDGE)
aggfb.Out.WrapT(gl2.CLAMP_TO_EDGE)
aggfb.Out.TexImage2D(0, gl2.RGBA16F, width, height, 0, gl2.RGB, gl2.FLOAT, nil)
aggfb.DiffUni = aprog.GetUniformLocation("diffusetex")
aggfb.NormalUni = aprog.GetUniformLocation("normaltex")
aggfb.PosUni = aprog.GetUniformLocation("postex")
aggfb.DepthUni = aprog.GetUniformLocation("depthtex")
gbuffer.ShadowMapUni = aprog.GetUniformLocation("shadowmap")
gbuffer.ShadowMatUni = aprog.GetUniformLocation("shadowmat")
gbuffer.NumPointLightUni = aprog.GetUniformLocation("NUM_POINT_LIGHT")
gbuffer.PointLightPosUni = aprog.GetUniformLocation("point_light_pos")
gbuffer.PointLightColUni = aprog.GetUniformLocation("point_light_color")
gbuffer.CamPosUni = aprog.GetUniformLocation("cam_pos")
//test data for cook torrance shader
gbuffer.CookRoughnessValue = aprog.GetUniformLocation("roughnessValue")
gbuffer.CookF0 = aprog.GetUniformLocation("F0")
gbuffer.CookK = aprog.GetUniformLocation("k")
aggfb.framebuffer.DrawBuffers(gl2.COLOR_ATTACHMENT0)
aggfb.framebuffer.Texture(gl2.FRAMEBUFFER, gl2.COLOR_ATTACHMENT0, aggfb.Out, 0)
gbuffer.AggregateFramebuffer = aggfb
return
}