第 22 课：View Space, Deeper UnderStanding

我的解：这里我的问题在于，忘了写转置

本课需 HLSL 顶点 / 纹理对象，暂以代码复盘呈现。

我的解

cbuffer Transform : register(b0) {
  float4x4 modelMatrix;
  float4x4 projectionMatrix;
};

struct VSInput {
  float3 position : Position;
};

struct VSOutput {
  float4 position : SV_Position;
  float3 wolrdPos : POSITION0;
};

#define CAMERA_POS float3(0.0, 2.0, 4.0)
#define CAMERA_ROTATE float3(-0.4, 0.0, 0.0)
float4x4 RotX(float a)
{
    float s = sin(a);
    float c = cos(a);
    return float4x4(
        1, 0, 0, 0,
        0, c,-s, 0,
        0, s, c, 0,
        0, 0, 0, 1
    );
}

float4x4 RotY(float a)
{
    float s = sin(a);
    float c = cos(a);
    return float4x4(
         c, 0, s, 0,
         0, 1, 0, 0,
        -s, 0, c, 0,
         0, 0, 0, 1
    );
}

float4x4 RotZ(float a)
{
    float s = sin(a);
    float c = cos(a);
    return float4x4(
        c,-s, 0, 0,
        s, c, 0, 0,
        0, 0, 1, 0,
        0, 0, 0, 1
    );
}
// Efficiently inverts a view matrix that
// contains only rotation and translation.
// Assumes the rotation part is orthonormal
// (i.e., no scaling or skewing), which is typical
// for camera view matrices in real-time rendering.
float4x4 InvertViewMatrix(float4x4 m) {
  float3 right    = m[0].xyz;
  float3 up       = m[1].xyz;
  float3 forward  = m[2].xyz;
  float3 position = m[3].xyz;

  float3x3 rotationInv = float3x3(
    right.x, up.x, forward.x,
    right.y, up.y, forward.y,
    right.z, up.z, forward.z
  );

  float3 positionInv = -mul(rotationInv, position);

  return float4x4(
    float4(rotationInv[0], 0.0),
    float4(rotationInv[1], 0.0),
    float4(rotationInv[2], 0.0),
    float4(positionInv,    1.0)
  );
}

VSOutput main(VSInput input) {
  VSOutput output;

  float4 worldPos = mul(modelMatrix, float4(input.position, 1.0));

  // setViewPosition
  float4x4 M_trans = transpose(float4x4(
    1,0,0,CAMERA_POS.x,
    0,1,0,CAMERA_POS.y,
    0,0,1,CAMERA_POS.z,
    0,0,0,1
  ));
  float4x4 M_rotate = transpose(mul(RotY(CAMERA_ROTATE.y),mul(RotX(CAMERA_ROTATE.x),RotZ(CAMERA_ROTATE.z))));

  float4x4 M_view_movement = mul(M_trans, M_rotate);
  float4x4 M_view = InvertViewMatrix(M_view_movement);
  float4 viewPos = mul(M_view, worldPos);
  output.position = mul(projectionMatrix, viewPos);
  output.wolrdPos = worldPos.xyz;

  return output;
}

复盘笔记

• 这里我的问题在于，忘了写转置