Typical Shader Setup
Here's a typical terrain rendering shader setup for Minecraft.
Notice:
viewRotis essentially amodelViewmatrix but Minecraft implements the position offset viaposition - camPosandmodelViewis merely used to express the camera rotation.
VS
glsl
#version 330 core
layout(location = 0) in vec3 position;
layout(location = 1) in vec4 color;
layout(location = 2) in vec2 texCoord0;
layout(location = 3) in vec2 texCoord1;
out vec2 TexCoord0;
out vec2 TexCoord1;
out vec4 Color;
uniform vec3 camPos;
uniform vec3 offset;
uniform mat4 viewRot;
uniform mat4 projection;
void main()
{
gl_Position = projection * viewRot * vec4(position - camPos + offset, 1.0);
TexCoord0 = texCoord0;
TexCoord1 = texCoord1;
Color = color;
}FS
glsl
#version 330 core
in vec2 TexCoord0;
in vec2 TexCoord1;
in vec4 Color;
out vec4 FragColor;
uniform sampler2D tex;
uniform sampler2D lightmap;
void main(void)
{
vec4 baseColor = texture(tex, TexCoord0);
vec4 lightColor = texture(lightmap, (TexCoord1 + vec2(8.0, 8.0)) / vec2(256.0, 256.0));
FragColor = baseColor * Color * lightColor;
}Render Setup
java
// pseudocode
program.use();
program.setUniform("modelView", MinecraftRenderUtils.getModelViewMatrix());
program.setUniform("projection", MinecraftRenderUtils.getProjectionMatrix());
program.setUniform("tex", 0); // meaning: pass the current bounded texture at texture unit 0
program.setUniform("lightmap", 1); // meaning: pass the current bounded texture at texture unit 1
program.setUniform("camPos",
MinecraftRenderUtils.getWorldOffset().x,
MinecraftRenderUtils.getWorldOffset().y,
MinecraftRenderUtils.getWorldOffset().z);
program.setUniform("offset", renderChunk.getPosition().getX(), renderChunk.getPosition().getY(), renderChunk.getPosition().getZ());
mesh.render();
program.unuse();Notice: You might want to check out the concept of texture unit. They are like slots and every slot can have a bounded texture.
Vertex Attribute
java
// pseudocode
BLOCK_ATTRIBUTE_LAYOUT.push(new Stride(28)
.push(new Slot(Type.FLOAT, 3))
.push(new Slot(Type.UNSIGNED_BYTE, 4).setNormalize(true))
.push(new Slot(Type.FLOAT, 2))
.push(new Slot(Type.SHORT, 2)));Camera Info Fetching
java
public Vector3f getWorldOffset()
{
// Do not plus eye height!!! This is why the function is named "getWorldOffset"
Entity camera = Minecraft.getMinecraft().getRenderViewEntity();
if (camera == null) camera = MethodHolder.getPlayer(Minecraft.getMinecraft());
double partialTicks = getPartialTicks();
double camX = camera.lastTickPosX + (camera.posX - camera.lastTickPosX) * partialTicks;
double camY = camera.lastTickPosY + (camera.posY - camera.lastTickPosY) * partialTicks;
double camZ = camera.lastTickPosZ + (camera.posZ - camera.lastTickPosZ) * partialTicks;
return new Vector3f((float)camX, (float)camY, (float)camZ);
}java
// this code snippet is from Minecraft class ActiveRenderInfo
// all you need to do is accessing MODELVIEW and PROJECTION via reflection
private static final FloatBuffer MODELVIEW = GLAllocation.createDirectFloatBuffer(16); // this is for viewRot
private static final FloatBuffer PROJECTION = GLAllocation.createDirectFloatBuffer(16); // this is for projection
Nullpinter