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62 lines
2.6 KiB
62 lines
2.6 KiB
#include <gtest/gtest.h> |
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#include "engine/displacement.hpp" |
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namespace devilution { |
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TEST(MathTest, WorldScreenTransformation) |
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{ |
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Displacement offset { 5, 2 }; |
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// Diablo renders tiles with the world origin translated to the top left of the screen, while the normal convention |
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// has the screen origin at the bottom left. This means that we end up with negative offsets in screen space for |
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// tiles in world space where x > y |
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EXPECT_EQ(offset.worldToScreen(), Displacement(-96, -112)); |
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// Transformation should be reversable (as long as it's not truncating) |
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EXPECT_EQ(offset.worldToScreen().screenToWorld(), offset); |
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// Tiles with y >= x will still have a negative y coordinate in screen space |
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offset = { 2, 5 }; |
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EXPECT_EQ(offset.worldToScreen(), Displacement(96, -112)); |
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// Most screen to world transformations will have a further displacement applied, this is a simple case of |
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// selecting a tile on the edge of the world with the default origin |
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const Displacement cursorPosition = { 342, -150 }; |
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EXPECT_EQ(cursorPosition.screenToWorld(), Displacement(0, 10)); |
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// Screen > World transforms lose information, so cannot be reversed exactly using ints |
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EXPECT_EQ(cursorPosition.screenToWorld().worldToScreen(), Displacement(320, -160)); |
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} |
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TEST(MathTest, NormalizeDisplacement) |
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{ |
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// Normalizing displacements transforms the value into 16 bit fixed point representations |
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Displacement vector { 5, 0 }; |
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EXPECT_FLOAT_EQ(vector.magnitude(), 5); |
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EXPECT_EQ(vector.normalized(), Displacement(1 << 16, 0)); // (1.0, 0.0) |
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vector = { 3, 4 }; |
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EXPECT_FLOAT_EQ(vector.magnitude(), 5); |
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EXPECT_EQ(vector.normalized(), Displacement(39321, 52428)); // ~(0.6, 0.8) |
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vector = { -5, 2 }; |
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EXPECT_FLOAT_EQ(vector.magnitude(), 5.3851647f); |
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EXPECT_EQ(vector.normalized(), Displacement(-60848, 24339)); // ~(-0.92, 0.37) |
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} |
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TEST(MathTest, MissileTransformation) |
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{ |
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// starting with a Displacement 2 world units West results in a vector pointing left of screen |
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EXPECT_EQ(Displacement(2, -2).worldToNormalScreen(), Displacement(-65536, 0)); |
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// if it's not normalizing the vector then it's a problem :D |
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EXPECT_EQ(Displacement(4, -4).worldToNormalScreen(), Displacement(-65536, 0)); |
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// Because of the isometric projection the y axis gets squashed |
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EXPECT_EQ(Displacement(8, 1).worldToNormalScreen(), Displacement(-40235, -25865)); // ~(0.6, 0.8/2) |
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// in elevation projection this would be a vector with x == y, isometric projection means y == x/2 |
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EXPECT_EQ(Displacement(8, 0).worldToNormalScreen(), Displacement(-46340, -23170)); // ~(0.7, 0.7/2) |
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} |
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} // namespace devilution
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