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REVIEWED: DrawSphereEx(), added educational info

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Ray 2024-06-30 11:15:45 +02:00
parent 953df38ac4
commit 13e3092511
1 changed files with 52 additions and 8 deletions
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60
src/rmodels.c
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@ -424,6 +424,48 @@ void DrawSphere(Vector3 centerPos, float radius, Color color)
// Draw sphere with extended parameters // Draw sphere with extended parameters
void DrawSphereEx(Vector3 centerPos, float radius, int rings, int slices, Color color) void DrawSphereEx(Vector3 centerPos, float radius, int rings, int slices, Color color)
{ {
#if 0
// Basic implementation, do not use it!
// For a sphere with 16 rings and 16 slices it requires 8640 cos()/sin() function calls!
// New optimized version below only requires 4 cos()/sin() calls
rlPushMatrix();
// NOTE: Transformation is applied in inverse order (scale -> translate)
rlTranslatef(centerPos.x, centerPos.y, centerPos.z);
rlScalef(radius, radius, radius);
rlBegin(RL_TRIANGLES);
rlColor4ub(color.r, color.g, color.b, color.a);
for (int i = 0; i < (rings + 2); i++)
{
for (int j = 0; j < slices; j++)
{
rlVertex3f(cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*i))*sinf(DEG2RAD*(360.0f*j/slices)),
sinf(DEG2RAD*(270 + (180.0f/(rings + 1))*i)),
cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*i))*cosf(DEG2RAD*(360.0f*j/slices)));
rlVertex3f(cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1)))*sinf(DEG2RAD*(360.0f*(j + 1)/slices)),
sinf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1))),
cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1)))*cosf(DEG2RAD*(360.0f*(j + 1)/slices)));
rlVertex3f(cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1)))*sinf(DEG2RAD*(360.0f*j/slices)),
sinf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1))),
cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1)))*cosf(DEG2RAD*(360.0f*j/slices)));
rlVertex3f(cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*i))*sinf(DEG2RAD*(360.0f*j/slices)),
sinf(DEG2RAD*(270 + (180.0f/(rings + 1))*i)),
cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*i))*cosf(DEG2RAD*(360.0f*j/slices)));
rlVertex3f(cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i)))*sinf(DEG2RAD*(360.0f*(j + 1)/slices)),
sinf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i))),
cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i)))*cosf(DEG2RAD*(360.0f*(j + 1)/slices)));
rlVertex3f(cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1)))*sinf(DEG2RAD*(360.0f*(j + 1)/slices)),
sinf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1))),
cosf(DEG2RAD*(270 + (180.0f/(rings + 1))*(i + 1)))*cosf(DEG2RAD*(360.0f*(j + 1)/slices)));
}
}
rlEnd();
rlPopMatrix();
#endif
rlPushMatrix(); rlPushMatrix();
// NOTE: Transformation is applied in inverse order (scale -> translate) // NOTE: Transformation is applied in inverse order (scale -> translate)
rlTranslatef(centerPos.x, centerPos.y, centerPos.z); rlTranslatef(centerPos.x, centerPos.y, centerPos.z);
@ -440,16 +482,18 @@ void DrawSphereEx(Vector3 centerPos, float radius, int rings, int slices, Color
float cosslice = cosf(sliceangle); float cosslice = cosf(sliceangle);
float sinslice = sinf(sliceangle); float sinslice = sinf(sliceangle);
Vector3 vertices[4]; // Store face vertices Vector3 vertices[4] = { 0 }; // Required to store face vertices
vertices[2] = (Vector3){0,1,0}; vertices[2] = (Vector3){ 0, 1, 0 };
vertices[3] = (Vector3){sinring, cosring, 0}; vertices[3] = (Vector3){ sinring, cosring, 0 };
for (int i = 0; i < rings + 1; i++) { for (int i = 0; i < rings + 1; i++)
for (int j = 0; j < slices; j++) { {
for (int j = 0; j < slices; j++)
{
vertices[0] = vertices[2]; // Rotate around y axis to set up vertices for next face vertices[0] = vertices[2]; // Rotate around y axis to set up vertices for next face
vertices[1] = vertices[3]; vertices[1] = vertices[3];
vertices[2] = (Vector3){cosslice*vertices[2].x - sinslice*vertices[2].z, vertices[2].y, sinslice*vertices[2].x + cosslice*vertices[2].z}; // Rotation matrix around y axis vertices[2] = (Vector3){ cosslice*vertices[2].x - sinslice*vertices[2].z, vertices[2].y, sinslice*vertices[2].x + cosslice*vertices[2].z }; // Rotation matrix around y axis
vertices[3] = (Vector3){cosslice*vertices[3].x - sinslice*vertices[3].z, vertices[3].y, sinslice*vertices[3].x + cosslice*vertices[3].z}; vertices[3] = (Vector3){ cosslice*vertices[3].x - sinslice*vertices[3].z, vertices[3].y, sinslice*vertices[3].x + cosslice*vertices[3].z };
rlVertex3f(vertices[0].x, vertices[0].y, vertices[0].z); rlVertex3f(vertices[0].x, vertices[0].y, vertices[0].z);
rlVertex3f(vertices[3].x, vertices[3].y, vertices[3].z); rlVertex3f(vertices[3].x, vertices[3].y, vertices[3].z);
@ -461,7 +505,7 @@ void DrawSphereEx(Vector3 centerPos, float radius, int rings, int slices, Color
} }
vertices[2] = vertices[3]; // Rotate around z axis to set up starting vertices for next ring vertices[2] = vertices[3]; // Rotate around z axis to set up starting vertices for next ring
vertices[3] = (Vector3){cosring*vertices[3].x + sinring*vertices[3].y, -sinring*vertices[3].x + cosring*vertices[3].y, vertices[3].z}; // Rotation matrix around z axis vertices[3] = (Vector3){ cosring*vertices[3].x + sinring*vertices[3].y, -sinring*vertices[3].x + cosring*vertices[3].y, vertices[3].z }; // Rotation matrix around z axis
} }
rlEnd(); rlEnd();
rlPopMatrix(); rlPopMatrix();