OpenSpace/modules/spacecraftinstruments/shaders/renderablePlanet_vs.glsl

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2022                                                               *
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#version __CONTEXT__

#include "PowerScaling/powerScaling_vs.hglsl"

layout(location = 0) in vec4 in_position;
layout(location = 1) in vec2 in_st;
layout(location = 2) in vec3 in_normal;

out vec3 vs_normal;
out vec2 vs_st;
out float vs_depth;

uniform mat4 modelTransform;
uniform mat4 modelViewProjectionTransform;
uniform bool hasHeightMap;
uniform float heightExaggeration;
uniform sampler2D heightTexture;
uniform bool meridianShift;


void main() {
  vs_st = in_st;

  vec3 tmp = in_position.xyz;
  
  // This is wrong for the normal. 
  // The normal transform is the transposed inverse of the model transform
  vs_normal = normalize(modelTransform * vec4(in_normal, 0.0)).xyz;
  
  if (hasHeightMap) {
    vec2 st = vs_st;
    if (meridianShift) {
      st += vec2(0.5, 0.0);
    }
    float height = texture(heightTexture, st).s;
    vec3 displacementDirection = normalize(tmp);
    float displacementFactor = height * heightExaggeration;
    tmp += displacementDirection * displacementFactor;
  }

  // convert from psc to homogeneous coordinates
  vec4 position = vec4(tmp, 1.0);
  vec4 positionClipSpace = modelViewProjectionTransform * position;
  vec4 p = z_normalization(positionClipSpace);

  vs_depth = p.w;
  gl_Position = p;
}